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FACTORY MANAGEMENT 
COURSE AND SERVICE 


A Series of Interlocking Text Books Written for the 
Industrial Extension Institute by Factory Man¬ 
agers and Consulting Engineers as Part 
of the Factory Management 
Course and Service 



INDUSTRIAL EXTENSION INSTITUTE 

INCORPORATED 


NEW YORK 






ADVISORY 

Nicholas Thiel Ficker, Pres., 
Pres. Ficker Recording Mch. 
Co. 

Charles E. Funk, Secy., 
Formerly Managing Editor, 
“Industrial Management .” 

Chas. A. Brockaway, Treas., 
Formerly Business Manager, 
The Engineering Magazine 
Co. 

Alwin von Auw, 

Gen. Mgr., Boorum-Pease Co. 

W. R. Basset, 

Pres. Miller-Franklin-Basset 
Co., 


COUNCIL. 

Charles C. Goodrich, 
Goodrich-Loclchart Co. 

Jervis R. Harbeck, 

Vice-Pres. American Can Co, 

Benj. A. Franklin, 

V-Prcs. Strathmore Paper Co. 
Major, Ordnance Dept., U.S.R. 

Willard F. Hine, 

Chief Gas Engr., Public Serv¬ 
ice Comm., N. Y. 

Irving A. Berndt, 

Mgr. Betterment Dept., Jos. T. 
Ryerson Co. 


Charles B. Going, 

Major, Ordnance Dept., U. S . R. 
Chairman Ex. Board, Soc. Industrial Engineers. 


STAFF AUTHORS. 

Willard L. Case, The Factory Buildings. 

Pres. Willard L. Case d Co., Cons. 

Engrs. 

David Moffat Myers, The Power Plant. 

Griggs d Myers, Cons. Engr. 

Joseph W. Roe, The Mechanical Equipment. 

Aeronautical-Mech. Engr., XJ. S. A. 

Albert A. Dowd, Tools and Patterns. 

Consulting Engineer. 

William F. Hunt. Handling Material in Factories 

Consulting Industrial Engineer. 

C. E. Knoeppel, Organization and Administra- 

Pres. C. E. knoeppel d Co., Cons. tion. 

Engrs. <, ' 

Meyer Bloomfield, Labor and Compensation. 

Head of Industrial Service Dept., 

Emergency Fleet Corp. 

George S. Armstrong, Planning and Time-Studies. 

Consulting Industrial Engineer. 

H. B. Twyford, Purchasing and Storing. 

Purchasing Dept., Otis Elevator Co. 

Nicholas Thiel Ficker, Industrial Cost-Finding. 

Pres. Ficker Recording Mch. Co. 

Dwight T. Farnham, Executive Statistical Control. 

Cons. Industrial Engineer. 

Charles W. McKay, Valuing Industrial Properties. 

Appraisal Engr., McMeen d Miller. 


TOOLS AND PATTERNS 


BY 


ALBERT A. DOWD 

u 

Member A. S. M. E. 

Consulting Engineer , Specializing in Machine Shop 
Planning and Tool Designing 


VOLUME 4 

FACTORY MANAGEMENT COURSE 


INDUSTRIAL EXTENSION INSTITUTE 

INCORPORATED 


NEW YORK 



Copyright, 1918, by 

INDUSTRIAL EXTENSION INSTITUTE 

INCORPORATED 




JUL 19 1918 

©CU503195 




i 


PREFACE. 


f 

i 

Many factory executives are chiefly concerned with the 
commercial end of their business, and yet do not possess the 
[) technical training to enable them to judge of the relative 
, value of the methods of production used in their own factory. 

In this they are at a decided disadvantage. Others, however, 
jJ do attempt to obtain a technical training while engaged in 
the management of their plant, and profit largely thereby. 
A thorough training along mechanical lines may not be neces¬ 
sary, but it is an excellent thing for the executive to familiar¬ 
ize himself at least with the fundamental principles under¬ 
lying mechanical work. 

Tool equipment needed to produce a given piece of work 
need not be understood in detail, but the executive should 
know the difference between a boring bar and a milling cutter, 
for instance, and should understand something of the reasons 
why one type of tool is more suited to the work in hand than 
another. He should also know what reasons there are for 
planing a piece of work instead of milling it; or boring and 
reaming instead of drilling. Pie should know what class of 
work requires fitting of such a character that the surfaces 
must be scraped in order to produce a proper bearing. He 
should understand something about the various machining 
processes, and also something about grinding. When a turn¬ 
ing operation is indicated and when a surface needs to be 
ground to secure accuracy are all essential points regarding 
which a progressive executive should be posted. In addition 
to these, the production of interchangeable work should be 
grasped in its fundamentals. He should further know the 
possibilities of gauging work to produce it with a minimum 


VI 


PREFACE 


of expense and within the required limits of accuracy con¬ 
sistent with the commercial quality of the product. If the 
executive does not understand something of these details he 
must depend entirely on his subordinates for information. 

In order to assist the progressive man and to enable him 
to secure concise data on tool equipment in a single volume, 
this book has been written and arranged. The intention of 
this treatise has been to take up the points mentioned in 
such a way that a non-technical man can readily grasp the 
fundamental principles underlying the matters pertaining to 
tool equipment. It is the belief of the author that executives 
will find themselves vastly benefited in their work by a care¬ 
ful study of its contents; for it is evident that the man who 
knows the essential principles underlying the design and up¬ 
keep of his tool equipment will be much more likely to obtain 
maximum efficiency in his product than another who is not 
so well posted. 


Albert A. Dowd. 


TABLE OF CONTENTS. 


CHAPTER I 

HAND AND FORGED TOOLS 

PAGE 

The Details of Manufacturing. 1 

Manufacturing Conditions. 2 

Interchangeable Manufacture. 3 

Tool Equipment. 5 

Classification of Hand and Forged Tools. 7 

Files. 8 

Hacksaws.10 

Cold Chisels.12 

Scrapers.15 

Forged Tools.19 

Grinding Tools.24 

Tools for Holders.25 

CHAPTER II 

DROP FORGING AND BLANKING DIES 

Principles of Drop Forging.26 

Dies for Drop Forging.28 

Blanking Dies.29 

Follow Dies.30 

Gang and Compound Dies.31 

Forming Dies.32 

Sub-Press Dies.34 

vii 





















TABLE OF CONTENTS 


via 

CHAPTER III 

DRILLING, BORING, AND REAMING 

PAGE 

Drills.35 

Core Drills.38 

Counterbores.39 

Reamers.41 

Inserted-Blade Reamers.43 

Taper Reamers.44 

Boring Tools.46 

Flat-Cutter Boring Bars.48 

Adjustable Boring Tool for Tool-Room Work ... 48 

Recessing Tools.50 

CHAPTER IV 

TURNING, FORMING, AND THREADING 

Hollow Mills. 55 

Turning Tools. 57 

Adjustable Turning Tools.58 

Open-Side Turning Tools.60 

Overhead Turning Tools.60 

Turning Tools for Vertical Boring Mills.62 

Cutting-off Tools.64 

Threading Tools.65 

Goose Neck Threading Tool.67 

Forming Tools. 68 

chapter v 

MILLING AND PLANING 

Milling Processes.. 72 

Factors Influencing Machine Selection ..... 73 

Milling Cutters. 75 

Slotting Cutters.. 78 

Angular and Special Cutters.. 79 























TABLE OF CONTENTS 


ix 

PAGE 

Gear-Toothed and Form Cutters.81 

Miscellaneous Cutters.83 

Interlocking Cutters.86 

Planing Tools. 87 

CHAPTER VI 

BROACHING 

The Purposes of Broaching.89 

Preliminary Treatment.90 

Broaching a Square Hole.91 

Broaching a Round Hole.92 

Four-way Key way Broaches.94 

Broaches for Irregular Holes.95 

CHAPTER VII 

SURFACE AND CYLINDRICAL GRINDING 

Grinding Material.97 

Grinding-Wheel Shapes.99 

Surface Grinding Methods.100 

Cylindrical Grinding.104 

External Taper Work.106 

External Form Grinding.106 

Internal Grinding.107 

Cylinder Grinding.108 

CHAPTER VIII 

SHOP EQUIPMENT 

Standard Equipment.110 

Surface Plates. Ill 

Straight-edges and Parallels.112 

Hand Vises.114 

C-Clamps.116 

V-Blocks.116 

Bench and Pipe Vises.117 



























X 


TABLE OF CONTENTS 


CHAPTER IX 

MACHINE EQUIPMENT 

PAGE 

Necessity for Proper Tools.119 

Drill Chucks and Sockets.120 

Tapping Attachment for Drill Press.123 

Collets and Chucks. 125 

Step Chucks.126 

Two-Jawed Chucks.. 127 

Geared Scroll Chuck.129 

Air-Operated Chucks. 130 

Four-Jawed Independent Chuck.132 

Machine and Manufacturing Vises ...... 134 

Taps, Dies, and Holders.136 

chapter x 

FIXTURES FOR PLAIN AND STRADDLE MILLING 

Nature and Variety of Fixtures.139 

Necessity for Proper Holding.140 

Milling Fixture for a Connecting Rod.141 

Straddle Milling Fixture Working from a Finished 

Surface.143 

Gang Milling...145 

End Milling a Slotted Bracket.145 

Fixture for Angular Milling.147 

Fixture for Form Milling.148 

Index Milling a Pair of Levers.149 

Index Milling Fixture for Quantity Production . , , 150 

CHAPTER XI 

FIXTURES FOR CONTINUOUS MILLING 

The Value of Simplicity. 154 

Continuous Milling Fixtures for Cylinder .... 156 





















TABLE OF CONTENTS xi 

PAGE 

Fixture for “Becker’’ Continuous Milling Machine . 158 

Spline-Milling Fixture.160 

CHAPTER XII 

FACE-PLATE FIXTURES 

Fixtures for Single Pieces. 164 

Fixtures for Quantity Production.165 

Fixtures for Cutting Packing Rings.166 

Face-Plate Fixture for a Hub Flange.167 

Self-Centering Fixture for a Rough Casting .... 168 

Fixture for Thin Aluminum Castings.169 

Fixture for an Irregular Bracket.172 

Counterbalanced Fixture for a Connecting Rod . . . 173 

Fixture with Adjustable Counterbalance . . . .175 

Eccentric Fixture for a Ring Pot.177 

Swinging Eccentric Fixture., 178 

CHAPTER XIII 

ARBORS AND MANDRELS 

Definition of Terms.181 

Arbor with Expanding Shoes.183 

Split Ring Expanding Arbor ........ 184 

Expanding Arbor for Automobile Flange .... 186 

Expanding Arbor for an Adjusting Nut .... 188 

Expanding Arbor for a Bevel Pinion.. 189 

Expanding Pin Chuck for a Piston.. 192 

Threaded and Knock-off Arbors.194 

Knock-off Arbor for Threaded Collars ..... 196 

Special Arbor for an Eccentric Packing Ring . . . 198 

CHAPTER XIV 

GENERATING AND FORMING ATTACHMENTS 

Generating Curved Surfaces ........ 200 

Simple Radius Generating Attachment ..... 201 




















TABLE OF CONTENTS 


xii 

PAGE 

Radius Forming Attachment for Crowning Pulleys . . 203 

Piston Forming and Grooving Attachment .... 206 

Angular Generating Cross-Slide.208 

Eccentric Turning Device for Packing Rings . . . 209 

Bevel Generating Attachment for a Turret Lathe . . 211 

Radius Generating Attachment for a Vertical Turret 

Lathe .214 

Angular Generating Attachment for Vertical Turret 

Lathe .216 

Internal Radius Boring Attachment.217 

chapter xv 

VERTICAL BORING MILL FIXTURES 

Fundamental Construction Features.220 

Vertical Boring Mill for Thin Work.221 

Special Fixture with Tapered Plug Locator .... 224 

Expanding Arbor and Faceplate for Vertical Boring 

Mill.226 

Vertical Boring-Mill Fixture for a Fragile Aluminum 

Casting.228 

Simple Fixture for Machining an Eccentric .... 231 

Sliding Fixture for Boring a Pair of Cylinders . . . 233 

Threaded Knock-off Arbor for Vertical Boring Mill . . 235 

CHAPTER XVI 

GRINDING FIXTURES 

Adaptability of Cutting Fixtures ..?.... 238 

Magnetic Chucks.240 

Grinding Fixture for Universal-Joint Part .... 241 

Piston Grinding Fixtures.243 

Internal Grinding Fixtures.244 

Grinding Fixture for Universal Joint Member ... 246 
















TABLE OF CONTENTS 


xiii 

PAGE 

Adaptable Fixture for Grinding Spur Gears .... 248 

Adjustable Fixture for Grinding a Bevel Pinion . . 250 
Grinding Fixture for a Large Bevel Spring Gear . . 251 

CHAPTER XVII 

OPEN DRILL JIGS 

Functions and Operation.253 

A Simple Plate Jig.256 

Plate Jig with Supplementary Supporting Ring . . 258 

Drill Jig for an Oil-Pump Cover.260 

Open Jig for a Lever.261 

Open Jig for a Lever with Stud Locater.263 

Open Jig for a Small Bracket.264 

Set-on Jig for a Transmission-case Cover.266 

Set-on Jig for a Gas^Control Plate.267 

CHAPTER XVIII 

CLOSED JIGS 

Bushing for an Oil-Pump Shaft.270 

Drill Jig for a Rod-Supporting Bracket.272 

Jig for Automobile Hand Lever ....... 274 

Drill Jig for a Bearing End-Cap.276 

Drill Jig for an Eccentric Bushing.278 

Drill Jig for a Radius Bracket.280 

Drill Jig for a Crooked Lever.283 

Large Trunnion Jig.284 

CHAPTER XIX 

LUBRICATION OF CUTTING TOOLS 

Necessity of Lubrication.289 

Composition of Cutting Lubricants.291 
















XIV 


TABLE OF CONTENTS 


PAGE 

Lubricating Compound for Steel . 293 

Cooling by Lubrication. 294 

Lubricating Stream to Remove Chips.295 

Lubricating Through the Spindle of a Turret Lathe . 296 

Flood Lubrication. 298 

chapter xx 

CUTTING FEEDS AND SPEEDS 

A Careful Study Required.301 

Definition of Cutting Speed.301 

Formula for Determining Cutting Speeds .... 302 

Relation of Speed to Feed.304 

Conservative Cutting Speeds.306 

Importance of Proper Speeds and Feeds.307 

Allowance for Exceptional Cases.308 

Effect of Lubricant on Feed and Speed.309 

General Rules . 310 

CHAPTER XXI 

PLANNING AND LAYING OUT WORK 

Tool Engineering Methods.315 

Preliminary Processes.317 

Preliminary Layout of Operation.318 

Machine-Tool Equipment.319 

Jigs, Fixtures, Tools, and Gauges.322 

Laying Out Operation Sheets. 323 

Free-Hand Sketches.330 

Making Layout Sheets.330 

Time Study Sheets .. 332 

Machine Tools Required. 334 

Setting Piece-Work Prices. 335 
























TABLE OF CONTENTS xv 

CHAPTER XXII 

ESTIMATING COSTS 

PAGE 

Time Factor in Estimating Costs.337 

Broad Experience Necessary.337 

Usual Causes of Failure. 339 

Skilled and Unskilled Labor ........ 340 

No Hard and Fast Rule.341 

A Manufacturing Case.342 

Overhead Expense—Hourly Basis.343 

Different Methods but One Principle.344 

CHAPTER XXIII 

INTERNAL, EXTERNAL AND THREAD GAUGES 
Accuracy Required in Interchangeable Manufacture . 346 

Terminology.347 

Terms Used in Gauging.349 

Setting Limits for Interchangeable Work . . . .351 

Marking Limits on Drawings.356 

Internal Limit Gauges.357 

Internal Taper Gauges.359 

Male Thread Gauges.362 

External Gauges.364 

Snap Gauges for Widths.366 

Templet Gauges.367 

Ring Gauges for Cylindrical Work.368 

Receiver Gauges. 370 

Taper Ring Gauges.372 

Master Taper Gauge for Female Gauges.373 

Female Thread Gauges ..374 





















TABLE OF CONTENTS 


xvi 


CHAPTER XXIV 

PROFILE AND INDICATING GAUGES 

Gauges for High Accuracy. 

Standard Instruments of Precision. 

Dial Indicator. 

Prestwich Fluid Gauge. 

Flush-Pin Gauges. 

Flush-Pin Gauge for Taper Shafts. 

Flush-Pin Gauge for Contours. 

Flush-Pin Gauge for Indicating Two Surfaces Simul¬ 
taneously . 

Indicator Gauge for Testing Alignment of Connecting- 

Rod Bearings.. 

Special Indicating Gauge for an Automobile Cam Shaft 
Feeler Gauge for an Automobile Crank Shaft 

Electrical Contact Gauge for Cams. 

Profile Inspection Gauge. 

Concentricity Indicating Gauge for High Explosive 

Shells. 

Johansson Gauges ,,,,,,,,,,, 


CHAPTER XXV 

PATTERNS 

The Use of Patterns. 

Form of Pattern. 

Method of Molding. 

Cores and Core Boxes. 

Two-Part Pattern and Method of Molding . 

Circular Cover Pattern. 

Pattern Requiring a Three-Part Flask 

Other Forms of Patterns. 

Tools for Pattern Making. 


PAGE 

376 

377 

379 

380 
385 

388 

389 

390 

391 
396 
399 

401 

402 

404 

405 


407 

408 

409 
411 
414 

416 

417 

418 

419 























TABLE OF CONTENTS xvii 

CHAPTER XXVI 

PATTERN RECORDS AND STORAGE 

PAGE 

Desirability of Pattern Records.421 

Quality of Patterns.422 

Economy in Combination Patterns.424 

Gear Molding Machines.425 

Pattern Record Cards.425 

Marking the Patterns.426 

Storing the Patterns.427 

CHAPTER XXVII 

CARE AND STORAGE OF CRUCIBLES 

Clay Crucibles.429 

Graphite Crucibles.430 

Storage of Crucibles. 432 



















TOOLS AND PATTERNS 


CHAPTER I 

HAND AND FORGED TOOLS 

The Details of Manufacturing. —Any machine tool 
in itself is of little practical use unless furnished with 
suitable cutting tools. So also any factory is incom¬ 
plete unless the shop equipment is efficient and the 
methods of handling the work are in accord with the 
most modern practice. The manufacturer who neg¬ 
lects these vital points and overlooks the many de¬ 
tails connected with his work, or who is satisfied 
with antiquated methods and equipment will eventu¬ 
ally find himself distanced in the race of progress by 
his more up-to-date competitors. Recent develop¬ 
ments in tool equipment and modern methods of 
handling are so far in advance of older methods of 
treatment that it is imperative for a successful manu¬ 
facturer to study the details of his equipment more 
carefully, so that his own judgment will enable him 
to stop the leaks which may be responsible for losses 
in production and to apply new principles which will 
bring his efficiency up to the maximum. 

The purpose of this book, then, is so to instruct 
the progressive executive in the various details upon 
which his success depends that he may be able to 
l 


2 


TOOLS AND PATTERNS 


judge intelligently of his shop equipment, to develop 
his methods of handling along the most approved 
mechanical lines, and to control economically his en¬ 
tire organization. In order to treat so extensive a 
subject logically, it will be necessary to separate it 
into several broad divisions, each of which may be 
again divided as seems desirable. 

Manufacturing Conditions. —In any factory the 
methods of handling work and the equipment most 
suitable for particular cases are largely dependent 
upon the product that is to be manufactured. The 
quantity produced is a very important factor, for it 
is obvious that methods can be developed to produce 
interchangeable work on a large scale when there is 
little likelihood of a change in design, and yet these 
same methods might not prove economical where the 
production was small and when there is a strong 
possibility of a change in design from time to time. 
Methods of handling, tool equipment, special ma¬ 
chines, and many other details must be planned in 
accordance with the work to be done. Now while the 
small manufacturer can not bring into use the many 
labor saving devices of the big producer, he can 
nevertheless profit by the other man’s experience 
and can develop similar processes, frequently, suit¬ 
able to his own work but on a smaller scale. It is 
therefore of the highest importance that he should 
become familiar with the best methods of manufac¬ 
ture as they have been developed by progressive 
people, and that he should study the application of 
principles to determine how far they may be applied 
to his own work. 


HAND AND FORGED TOOLS 


3 


Many instances are seen where a small manufac¬ 
turer runs along “in the same old rut” year after 
year and even makes a comfortable income for a 
time, until at last his dwindling profits show him that 
something is radically wrong and that he must look 
into some of the details of manufacture more closely 
or be content with a much smaller profit than 
formerly. Evidently a condition of this kind does not 
develop at once; it is a gradual process and there¬ 
fore is much harder to combat. When such a con¬ 
dition first becomes apparent, a course of treatment 
is necessary in order to prevent further losses. In 
actual practice, though, it is difficult for a manufac¬ 
turer to realize that he is losing ground, because it 
seems to him that he is continuing along the same 
lines that he has followed with success for a number 
of years. 

This state of affairs may be likened to a slow pro¬ 
cess of decay or a lingering disease which becomes 
chronic after a considerable period of time. The best 
of all remedies for a disease of this kind is knowl¬ 
edge. As the manufacturing world progresses, and 
as new methods are developed and applied, the execu¬ 
tive must keep pace with his competitors and profit 
by their experience as far as possible. 

Interchangeable Manufacture.— Strictly speaking 
the process of interchangeable manufacture is applic¬ 
able only to high production work when a great 
number of parts of the same kind are to be manu¬ 
factured. When parts are truly interchangeable any 
one part can be used in the place of another without 
the necessity for hand fitting. In an automobile, for 


4 


TOOLS AND PATTERNS 


example, a broken part can be replaced with a new 
one with the assurance that the new part will fit as 
well as the old. Theoretically an entire machine can 
be built by the interchangeable system in such a way 
that all the parts can be assembled to make a per¬ 
fect whole without the need of any fitting. Practic¬ 
ally, however, there may be a few parts that must be 
‘ 4 touched up” with a file here or there, or there may 
be a hole drilled at assembly in order to complete the 
mechanism. But it is an accepted fact that by the 
greatest care in manufacturing and by a proper sys¬ 
tem of gauging and inspection, hand fitting and ma¬ 
chining operations at the time of assembling can be 
done away with entirely. 

When any product is to be manufactured on the 
interchangeable system, the gauging of the various 
components and the system of inspection are of 
supreme importance. The various parts which go to 
make up the completed product must be manufac¬ 
tured in such a way that there will be no more 
variation in size than the nature of the mechanism 
will permit, and this variation must be held within 
carefully fixed limits. For this purpose gauges must 
be made such that they can not be applied to the 
work if the variation is too great. 

By means of limit plug gauges for the inspection 
of holes and limit snap gauges for outside dimensions 
any number of male pieces can be made to fit corre¬ 
sponding female pieces in the desired manner. 
Shoulder distances, flanges, contours of irregular 
parts, and many other kinds of fits can be held within 
the desired limits of accuracy by a proper system of 


HAND AND FORGED TOOLS 


5 


gauging. The matter of allowances for fits of vari¬ 
ous kinds must be most carefully worked out accord¬ 
ing to the nature of the product to be manufactured. 
Thus, the allowances made for running fits in a piece 
of farming machinery would be much greater than 
in a high-grade automobile, and yet the parts would 
he interchangeable in the one case as well as in the 
other. 

Tool Equipment.—The tool equipment for any fac¬ 
tory may be divided into two broad groups, perish¬ 
able tools and permanent tools. For purposes con¬ 
nected with cost finding these groups can be separated 
by a more or less flexible line, but from the mechani¬ 
cal standpoint this grouping is by no means specific 
enough and can not, therefore, be followed out logi¬ 
cally without causing more or less confusion. For 
example, it is evident that files or hacksaws are 
perishable tools, because they wear out in use and 
can only be replaced by new ones as they cannot be 
re-sharpened. On the other hand, jigs and fixtures, 
surface plates, and other tools of like character may 
be classed as permanent tools because their lives are 
very long and they can be maintained and put in 
good condition at a nominal cost, unless of course 
they are accidentally broken. As this book deals with 
the mechanical aspect of the tool situation rather 
than the cost finding end of it, I shall consider the 
mechanical viewpoint in this discussion, keeping in 
mind and giving due consideration, however, to the 
matter of upkeep in specific cases. 

It is doubtless better to consider tools from the 
standpoint of the work which they do than in any 


6 


TOOLS AND PATTERNS 


other way, although the machine on which the tools 
are used will also have a certain effect on the group¬ 
ing. For example, a drill is used for drilling a hole 
and it is frequently used on a drilling machine or 
drill press. So also a turning tool is used for turning, 
a recessing tool for recessing, a threading tool for 
threading, a reamer for reaming, and a tile for filing. 
It can readily he seen, then, that the cutting operation 
on the work has a positive effect on the name of the 
tool. Some tools which will be described herein, are 
not used in machines but are hand tools, such as 
files, scrapers, cold chisels and the like. Other tools, 
again, such as surface plates, vises, and so on, can be 
readily grouped under shop equipment. Tools such 
as chucks, face plates, tool holders, etc., form a part 
of the machine equipment, and are therefore classed 
in this way. Other tools are grouped according to 
the kind of work for which they are intended or by 
the machine on which they are to be used. 

Any factory depends for its success upon the effi¬ 
ciency of its tool equipment, and it is therefore of 
the highest importance that these tools should be so 
well designed, carefully made, and maintained that 
no loss of production can ever be laid to their in¬ 
efficiency. In discussing the purposes and applica¬ 
tion of tool equipment and kindred subjects treated 
here, cases will be cited which are for a large part 
fundamental in their application. Complicated de¬ 
sign and intricate mechanisms will not be considered. 
The executive, who may not be a strictly mechanical 
man, will find that the principles involved and the 
instances noted are well within his mechanical scope. 


HAND AND FORGED TOOLS 


7 


The superintendent or foreman may discover that 
mechanical features are treated in such a way as to 
bring out many new points of interest. The shopman 
and mechanic will appreciate many practical exam¬ 
ples which are given; and the designer may profit 
largely by his technical knowledge which will give 
him a more intimate understanding of many interest¬ 
ing points in design treated, perhaps, in an entirely 
new way. 

Classification of Hand and Forged Tools. —Files, 
cold chisels, and scrapers are essentially hand tools. 
Hacksaws also come under this grouping, although 
they are often driven by power for cutting off stock 
from bars. Forged tools are used in so many forms 
and shapes and for so many purposes that their 
grouping is a difficult proposition. On this account 
I have included them in a separate group in this 
chapter, regardless of their shape or form or the 
class of machine they are to be used with. But be¬ 
cause there are so many shapes of forged tools, the 
subject will be treated broadly, with a few general 
hints on the theory of cutting, the proper angles of 
the tool, and so on. 

In the descriptions in this volume of the various 
tools I have aimed to give principles and points of 
particular value, but I have made no attempt to cite 
every variety of tool. Rather my purpose has been 
to give a broad general classification which will be 
of the greatest value without too technical a treat¬ 
ment. Important points in connection with upkeep 
and economy of operation will be noted from time 
to time. 


8 


TOOLS AND PATTERNS 


Files. —In general there are three classes of files in 
common use, their classification being dependent upon 
the kind of cuts which form the teeth. The three 
classes are rasps, single cut, and double cut. The 
types or classes are graded according to length and 
fineness of the teeth and are specified as rough, coarse, 
bastard, second cut, smooth, and dead smooth. The 
lengths of the various files are from four to sixteen 
inches, and each length of each class has its own 
grade determined by the number of teeth to the inch 
(or “pitch,” as it is sometimes called). The fineness 
of the teeth being proportional to the length of the 
file it is evident that the term second cut, for ex¬ 
ample, does not indicate the size of the teeth unless 
the length of the file is also known. 

Files are of numerous forms to suit various kinds 
of work, the flat, half round, round or “rat-tail,” 
triangular, and square forms being most commonly 
used. Files of these varieties are full tapered or 
tapered in both thickness and width for about two- 
thirds of their length, the remaining third having 
nearly parallel edges. A warding file tapers in width 
but not in thickness, while pillar and hand files taper 
in thickness but have parallel edges. Saw files and 
equaling files are nearly of the same size for their 
entire length. The tang of a file is the part to which 
the handle is fitted and the heel is the part next to 
the tang. When one edge of a file is smooth it is 
termed a “safe” edge. The various methods of cut¬ 
ting file teeth are shown in Figure 1 together with 
several cross-sectional forms. 

Since files are used for a great variety of work in 


HAND AND FORGED TOOLS 


9 


any factory their cost becomes an item of considerable 
importance. It behooves an executive to see not only 
that the files ordered are of the proper grades, but 
that they are used as they should be and for the work 
for which they are intended. It is evident, therefore, 
that the selection of a file for a given piece of work 
is worthy of a certain amount of attention. For ex¬ 
ample, in selecting files for any work it is necessary 



to know the kind of metal to be cut, whether the 
surface to be worked is broad or narrow, whether 
the metal is wrought or cast, and whether it is to be 
smooth or draw-filed or will be finished in some other 
way. A rough-cut or coarse file would be used on a 
broad surface if much metal is to be removed, and a 
new file would be used rather than an old one if the 
material is a casting. A file which has been some¬ 
what worn can be used on wrought work to advan¬ 
tage, but it would not give good results on a casting. 
In general, thin files are to be avoided, except in the 
hands of a skillful workman, for they are very apt to 
produce a rounded surface. 

In filing wrought metals a little oil or turpentine 
may be used on the face of the file so that the file 














10 


TOOLS AND PATTERNS 


will “take hold” better, but cast metals should 
always he cut dry. Chalk rubbed on the file teeth 
when filing castings will prevent clogging, and the 
use of a file card (a wire brush for cleaning the 
teeth) cannot be too strongly recommended. When 
a file becomes clogged the depth of the cut is reduced 
and slower work is the outcome; and on wrought 
metals chips will pack into the file teeth and scratch 
the work unless the file is kept clean. Again, many 
files are ruined by being used on the scale of a cast¬ 
ing; the edge of the file only should be used to get 
below the scale and then the flat side can be used to 
advantage without injury to the teeth. Proper care 
of a file consists in careful handling, suitable selec¬ 
tion, and a thorough cleaning. When oil or turpen¬ 
tine has been used on a file, it can be given several 
applications of chalk which will absorb the moisture 
and bring out the chips between the teeth, so that it 
will be clean and ready for the next job of work. 

Hacksaws.— Hacksaws are of two varieties, those 
used in hand-saw frames and those used on power- 
operated sawing machines. A number of years ago 
hacksaw teeth were punched, but at present this 
method is little used and the teeth are now milled. 
The hacksaw blade used in hand hacksaw frames is 
little different from the machine saw blade except 
that it lighter and not adapted to such heavy service. 
The teeth of hacksaws are “set” in different ways 
to suit different cutting requirements, and the prac¬ 
tice of various manufacturers differs somewhat in 
this regard. For example, considering the teeth as 
set over an each side of an imaginary center line, one 


HAND AND FORGED TOOLS II 

maufacturer may make a saw blade with every alter¬ 
nate tooth set out from each side of the line; another 
may be made with two teeth set out the same dis¬ 
tance from the center line and an intermediate tooth 
on the center line; a third variety may have two 
teeth on one side, one tooth on the center and then 
two teeth on the other side; while still another may 
have one tooth set out a certain distance on one side 
of the center line, the next tooth set out the same dis¬ 
tance on the other side of the center line, then two 
teeth set out not quite as far on each side of the 
center line and a fifth tooth set on center. These 
variations in the setting of the teeth are not followed 
to any great degree by different manufacturers, al¬ 
though certain claims in regard to their value for 
different classes of materials may have considerable 
value. 

Ordinarily hacksaw blades have one tooth set to 
the right, the next to the left, and the third one on 
the center line. The teeth which are set out from the 
center widen and deepen the cut of the saw, while the 
straight teeth in the center tend to keep the cut free 
from chips. The tooth spacings commonly used vary 
from nine teeth to the inch to thirty-two teeth to the 
inch. Speaking generally, saws having the coarser 
spacing should be used on soft materials, such as 
wood, fibre, or soft metal. The finer spacings are 
better for hard metal, because they are less likely to 
4 ‘strip.’’ For the average work in the machine shop 
for hand work blades having eighteen teeth to the 
inch are recommended, while for machine work blades 
with twelve to fourteen teeth to the inch are most 


12 


TOOLS AND PATTERNS 



9-TEETH TO THE INCH 


PIG. 2 . TOOTH SPACING IN HACK-SAW BLADES 
(Slightly Reduced) 

economical. A comparison of the tooth spacings will 
be found in Figure 2. 

To obtain the best results in using hacksaws, 
whether for machine or hand work, the blade should 
be well strained in the frame to insure true cutting 
and to prevent breakage. The selection of the proper 
saw blade for a given class of work makes a great 
difference in the efficiency obtained. 

Cold Chisels. —Cold chisels are made in many forms 
and for various classes of work, such as chipping, 
key-seating, oil-grooving, cornering, and prick-punch¬ 
ing for correcting errors in drilling and also for lay¬ 
ing out work to be machined. When castings are 
received from the foundry, often they will be found 
with ragged edges or other inequalities which, unless 
removed before machining, would interfere with their 








HAND AND FORGED TOOLS 


13 


handling. Several methods are used to smooth up 
the surfaces; small castings are ‘ 4 snagged’’ on a 
coarse grinding wheel which is mounted on a spindle 
in a heavy floor stand; larger work is roughed off 
with a smaller wheel, one that may be operated by a 
flexible shaft suitably counterbalanced to facilitate 
handling or mounted on a small truck and operated 
by an electric motor. Or large work may be chipped 
with a cold chisel, usually one operated by compressed 
air in a chipping hammer, or by hand in some cases. 
Compressed-air chipping hammers are very rapid in 
their action and can be made to cover a considerable 
amount of surface in a remarkably short time. Hand¬ 
chipping operations are much slower but can be used 
for purposes not adapted to machine chipping. 

A number of forms of cold chisels are shown in 
Figure 3. The tool, A, is known as a flat chisel; B, 
a cape chisel; C, a round nose chisel or gouge; D, the 
cow-mouth; E, diamond point, and F, a straight-side 
chisel. An important point in connection with cold 
chisels is the angle of the edges in relation to the 
cutting point, as these edges serve as guides in chip¬ 
ping operations. Figure 4 shows, at A and B, the 
manner in which these edges act as guides when work 
is being done. Taking the flat chisel as an example 
and referring to the diagram shown in Figure 4, it 
will be seen that the angle of the edge, as indicated 
at A, tends to shear the metal on the upper side and 
acts as a guide on the lower surface of the chisel to 
prevent too deep cutting. In the example B, the tool 
has been ground incorrectly, so that there is no shear¬ 
ing action on the metal and the tendency is for the 


14 


TOOLS AND PATTERNS 


r 


II - . ~3 3 

A-' 



C •' 


(c§ :: . 

D-*' 



FIG. 3 . DIFFERENT FORMS OF COLD CHISELS 


chisel to gouge down into the work and not produce 
a good cutting action. 

The cape chisel, B, in Figure 3, is made so that the 
point is narrow and tappers back slightly to give 
clearance when cutting a key way or something of 
this kind. This clearance also prevents upsetting the 
metal and raising a burr along the edges of the groove. 
So also the gouge, C, has a slight amount of back clear¬ 
ance to facilitate the cutting action. This type of 















































HAND AND FORGED TOOLS 


15 



FIG. 4 . EFFECT FROM INCORRECT AND CORRECT ANGLES ON 
COLD CHISELS 


chisel is used largely for cutting oil grooves in bear¬ 
ings, pulleys, and similar work. It will be seen that 
this type of chisel is ground at a different angle than 
the cape and flat chisels. This is done so as to per¬ 
mit the operator to change the depth of the cut by 
raising the end of the chisel a trifle while in use. 
The cow-moutli chisel is used for chipping circular 
work; while the diamond point, shown at E, is used 
for correcting errors when drilling holes, for chip¬ 
ping in the corners of dies, and such work. The 
straight-side chisel, shown at F, is commonly used by 
die makers for squaring up the sides of punches and 
dies and for squaring out holes, cutting shoulders, 
and the like. 

Scrapers.—After a piece of work has been ma¬ 
chined, the eye is deceived into thinking that the 
resulting plane surface is smooth and free from 
humps and hollows. As a matter of fact, however, 












16 


TOOLS AND PATTERNS 


the apparently smooth surface is much like the waves 
of the ocean on a small scale; hence, if it is neces¬ 
sary to have a perfectly fitting piece of work, the 
‘ 4 high spots” must be removed and the whole sur¬ 
face worked down more nearly level. These high 
spots can only be levelled by hand with scraping 
tools. It may seem strange to the layman that a 
piece of work, if properly clamped, cannot be finished 
to a true surface on a high class machine tool, and 
if the machine tool itself is in first class working 
condition, but even under the most favorable con¬ 
ditions there is bound to be a certain amount of 
“spring” both in the work being machined and in 
the tool which is cutting it. Hence, work which has 
been machined shows an infinite number of high and. 
low spots more or less evenly distributed over the 
surface. If two moving parts were to be fitted to¬ 
gether with these high and low spots still upon them, 
it would only be a short time before the wearing 
down of the spots would destroy the alignment of the 
pieces, seriously impairing their accuracy. As an 
example, consider the “ways” of a planer or of a 
turret lathe: In the planer, if the ways were not 
scraped to a perfect bearing one side would be very 
apt to wear more than the other, so that the work 
produced would not be accurate—it might be taper¬ 
ing, convex, concave, or even a combination of all 
inaccuracies mentioned. In the case of the turret 
lathe, the center of the turret would not line with the 
spindle after a short while, and the holes bored and 
surfaces turned would be tapering or otherwise dis¬ 
torted. 


HAND AND FORGED TOOLS 


17 


It will be seen from the foregoing that on flat work 
it is necessary to scrape all surfaces which are to be 
in moving contact with other flat surfaces. When 
their contact is with cylindrical bearings, they may 
be scraped, lapped, or ground according to the par¬ 
ticular requirements. The art of scraping requires 
practice, a nice sense of touch, and a considerable 
amount of judgment. Many people not conversant 
with the necessity of scraping bearing surfaces, 
imagine that the mottled effect produced is for orna¬ 
mental purposes, yet it is highly essential on any 
well-made machine and serves no other purpose than 
that mentioned. 

Many varieties of scrapers have been designed 
simply to fulfill a need for a tool to get at some par¬ 
ticular piece of work of unusual form on which a 
bearing was desired. In Figure 5 is shown a double¬ 
end scraper, A, commonly used on plane surfaces and 
broad work. It will be seen that this type has a 
broad flat surface and is perfectly square across the 
end. Such scrapers are often made single-ended from 
an old file, having a wooden handle on one end; but for 
heavy work the double-end tool shown is to be pre¬ 
ferred, for it is not likely to spring and its weight 
gives an added advantage. It is important that any 
scraper of this type should be ground perfectly 
square across the end so that it will not tend to gouge 
work when in use. 

Scrapers are hardened to as high a degree as fire and 
water and the metal itself will permit. The scraper, B, 
in Figure 5 is hook shaped, which permits it to be 
pulled toward the workman instead of pushed away 


18 


TOOLS AND PATTERNS 



from him, as in the case of the donble-end scraper. The 
triangular form, C, is sometimes made from a three 
cornered file from which the teeth have been ground 
away. All scrapers are made of high-grade steel, as 
the service to which they are put is so severe that no 
economy would be found in using low-grade steel for 
the purpose. Scrapers of the three-cornered variety 
are largely used for scraping bearings of cylindrical 
form, such as the crank-shaft bearings in an auto¬ 
mobile, or spindle bearings in machine tools. 

When flat surfaces are to be scraped, a 4 ‘master’’ 
or standard surface plate is used and the parts to be 
fitted are rubbed on it to determine the high spots. 
In using this master plate a very light coating of 
Prussian blue, red lead, or lamp black is spread upon 
the machined work which is then rubbed upon the 
master plate; the high spois on the machined piece 
show bright and are removed with the scraper. This 
performance is repeated until the work shows an 
even bearing all over. When completed a series of 
high-point bearing spots very close together is ob- 


















HAND AND FORGED TOOLS 


19 


tained all over the work, so that it has the mottled 
appearance previously mentioned. 

Forged Tools. —All varieties of work on nearly 
every class of machine tool require the use of forged 
tools. Many shapes and forms are adopted, depend¬ 
ing on the work for which they are intended. Gen¬ 
erally speaking, their construction is such that they 
can be ground several times before reforging is neces¬ 
sary. On lathes and planers they are used to a 
greater extent than on any other classes of machines, 
and many tools of the same general type can he used 
on these two machines. 

A group of lathe and planer tools, which may be 
considered as representative types is shown in Figure 
6, although many modifications are required to suit 
particular cases. It is unnecessary to take up each 
of the tools illustrated and describe its functions, for 
the reason that tools of this kind are so well known 
that they require little description and can be found 






































20 


TOOLS AND PATTERNS 


in every modern factory as well as in those of older 
days. 

The matter of upkeep of cutting tools, however, is 
a subject which should receive most careful attention; 
and as the upkeep and productive capacity of any 
tool is dependent upon its shape we will consider the 
points which are important in regard to cutting 
angles and shapes of the several varieties of tools. 

It is evident that any kind of cutting tool, to pro¬ 
duce its maximum amount of work, should be so 
shaped and ground that it will remove the metal with 
the least possible amount of friction. When such a 
condition is reached the machine tool is at its best, 
and the work is produced with a minimum amount 
of labor. Further than this, the life of the tool is 
prolonged because the periods of regrinding are 
lessened. 

The simplest types of tools are used on planer 
work, for the reason that the cutting action of the 
planer is along a straight line. On the other hand, 
a lathe tool is also used on the outside of cylindrical 
work, in boring a hole, or in turning a taper, so that 
in each case the tool must be differently shaped in 
order to clear itself and “turn the chip” to the best 
advantage. 

A number of factors must be considered in the de¬ 
sign of cutting tools, such as the position of the tool 
in relation to the work, the spring of the tool under 
the cutting action, the shape of the work, and the 
material to be cut. For example, soft and fibrous 
materials require an entirely different cutting angle 
than do materials having a short-grained structure. 


HAND AND FORGED TOOLS 


21 


The tool, A, shown in Figure 7, is seen to be im¬ 
properly designed for planer work, because an excess 
of power is required to pull the tool and, further¬ 
more, it really does not cut at all but crowds or 
pushes the metal off. If such a tool were used for a 
long while under the condition shown it would in 



FIG. 7 . THE CUTTING ACTION OF PLANER TOOLS 
(A) Incorrect Form of Cutting Tool. (D) Abrasive Action of 
Chips on Face of Tool. 


time develop a form similar to that shown at D in 
the illustration, because of the abrasive action of the 
chips against the tool. It would be perfectly logical 
to assume, then, that if the tool were ground to this 
shape in the first place its form would be more nearly 
correct. 

The manner in which any cutting tool is supported 
determines to a certain extent its shape, because the 
spring of the tool holder may tend to carry it into 














22 


TOOLS AND PATTERNS 


the work and produce “chatter .’ 9 An example of 
this kind is illustrated in the planer tool, A, Figure 
8. As the work moves in the direction indicated by 
the arrow, the tool and tool block together will 
spring (if sufficient pressure is applied), radially from 
the corner B with a tendency to dig into the work. 



FIG. 8. PLANER TOOLS 

(A) The Digging Tendency of Tools Productive of Chatter. 
(C) Tool Springs Away from Work and Does Not Dig in. 


For this reason the tool may be made as shown at C, 
with the cutting point far enough back so that any 
spring action will carry the tool away from the work, 
thus obviating “chatter.” The heel angle of a cut¬ 
ting tool should be of such shape as to resist the 
cutting strain to the best advantage. It is obvious, 
therefore, that heavy cutting tools, such as those 
used on a planer, should have a greater body of metal 
and less clearance behind the cutting edge than those 
used for a lighter class of work. 

The diamond-point tool, shown in Figure 9, is a 
common type of lathe tool, but such a tool is limited 

















HAND AND FORGED TOOLS 


23 


in its productive capacity by the width of the cut¬ 
ting face and the strength of the neck. It is not 
suited to high-speed work nor to fine finishing, ex¬ 
cept on wiry material such as tool steel or alloy 
steels. In work of this nature it may be used for 
finishing, providing that a very fine feed is given 



FIG. 9 . DIAMOND-POINT FIG. 10 . SIDE TOOL FOR 

LATHE TOOL ROUGHING DOWN WORK 


the machine tool and a slight “drag” is stoned just 
behind the cutting point so as to produce a burnish¬ 
ing effect on the work. Many mechanics use a side 
tool such as that shown in Figure 10 for roughing- 
down bar stock, for the cutting face of the tool is 
wide and it can be made to take a very wide chip if 
set as indicated in the illustration. 

In addition to the points above mentioned, when a 
cutting tool is to be used on cylindrical surfaces, as 
in the case of a lathe job, the position of the tool 
relative to the center of the work is of importance. 
Theoretically a tool should be “on center,” whether 
it is boring a hole or turning an outside cylindrical 
surface. It must be remembered, however, that the 
majority of tools are more or less elastic and will 
show a certain amount of spring which must be taken 

















24 


TOOLS AND PATTERNS 


into consideration in setting the tool. Hence, if an 
outside diameter is to be turned, for example, the 
tool should be set slightly below center so that it 
will not dig in under the pressure of the cut but will 
rather tend to spring away from the work. Similarly, 
in boring a hole the tool should be slightly above 
center so that its spring under the cutting action 
will also carry it away from the work. But as previ¬ 
ously mentioned these points will depend entirely upon 
the manner in which the tools are supported and upon 
the direction which their deflection will take under the 
cu-tting strain. 

Grinding Tools. —In past years it has been the 
custom for mechanics to grind their own tools to any 
particular kind of a shape that they fancied gave the 
best results. The natural consequence of a procedure 
like this was that one man’s work would be much 
superior to another’s because of a greater knowledge 
of tool shaping. At present, however, it is possible 
to purchase a tool grinder for forged tools so that 
all tools of any particular variety can be ground to 
a predetermined angle, even by an inexperienced man. 
The work produced with tools uniformly ground is 
much superior to that done by a “hit or miss” 
method, and the life of the tool is correspondingly 
prolonged. In addition, the amount of time lost in 
regrinding tools is greatly reduced and the labor of 
a skilled mechanic is not required. In determining 
proper angles for cutting tools the aim should be 
toward the ideal form which will turn the chip to the 
best advantage with the least amount of power and 
at the same time to give the longest life to the tool. 


HAND AND FORGED TOOLS 


25 


Especial caution should be exercised not to obtain 
an angle so sharp that the cutting edge will approach 
the wood tool in shape, for a tool with such an edge 
would have a very short life and would require fre¬ 
quent regrinding. 

Tools for Holders. —In order to economize in the 
amount of high-speed steel used in forged tools a 
number of holders have been devised which require 
only small sections of such steel. These holders are 
so arranged that they will take stock of standard 
sizes and clamp them securely; in this manner they 
will answer many purposes of forged tools made from 
high-speed steel, or certain clesses of work they are 
extremely valuable; but for very heavy cutting forged 
tools are still preferred in many factories because 
the heavy forged tools have a greater section and 
carry away the heat more rapidly than the smaller 
sections used in holders, and are therefore capable of 
higher speeds and greater production. This fact, 
however, does not detract in any way from the utility 
and economy of the holders mentioned. These holders 
will be described in more specific detail in the dis¬ 
cussion of tool holders. 


CHAPTER II 


DROP FORGING AND BLANKING DIES 

Principles of Drop Forging 1 . —Although drop forg¬ 
ing dies may he re-cut when they become greatly 
worn, they should still he considered as perishable 
tools; a great deal depends upon the treatment of the 
die, both in the process of hardening and also in its 
use. The construction and form of the die itself 
makes a great difference in its life, and it is difficult 
to estimate the number of pieces upon which any die 
can be used on account of the variations in the form 
of pieces to be drop forged. When a comparatively 
small number of pieces are to be made, it is possible 
to make up cast iron dies, but of course these are 
not serviceable for any length of time. When only 
six or eight similar pieces are to be made cast iron 
dies are most economical. But in work requiring a 
large production the dies are made of steel containing 
from 0.45 to 0.60 per cent carbon, and the blocks from 
which they are cut range between 5 and 8 inches in 
thickness. Usually the dies are dovetailed, as shown 
in Figure 11, to fit the drop hammer in which they are 
to be used. 

Since the advent of the automobile, drop forging 
processes have been greatly perfected, and many 
forgings are now made which would have been con- 
26 


DROP FORGING AND DIES 


27 



2_X 


FIG. 11 . DOVE-TAILED DROP FORGE DIES 

sidered impracticable a few years ago. The necessity 
for extraordinary strength in certain parts has led 
to the adoption of alloy steels for these pieces and 
drop forgings are made to suit the conditions. 

Comparatively few pieces of work have a form 
such that they can be produced in a single pair of 
dies. When the diameters do not vary greatly in the 
different sections, circular forms can be made in a 
single set of dies; but forms of widely varying sec¬ 
tion require a preliminary “breaking down” opera¬ 
tion, and when a heavy boss is a part of the forging 
three or four operations may be necessary before the 
piece is completed. When the forgings are small, 





















28 


TOOLS AND PATTERNS 


several recesses can be made in one set of dies for 
breaking down, formation, cutting off, and nicking 
for breaking off. Generally speaking, it is best to 
complete a forging at a single beat if possible, but in 
some instances several beats may be necessary. When 
work is of large size and two or more sets of dies are 
used, the hammers can be placed near each other, so 
that the workman can step immediately from one to 
the other without “losing the heat.” 

In work done on the anvil by hand the smith acts 
as an artist and models his work to the form re¬ 
quired, drawing it out here or there as the design may 
call for. But wTien forgings are made in dies, the 
amount of metal from which a piece is stamped must 
be large enough so that it will overrun the die a 
trifle, thus assuring a full die and a forging of proper 
shape. The “fin” which is squeezed out between the 
dies at the time of forging must be removed by means 
of trimming dies. Provision is made in the dies 
themselves to take care of this fin, as shown in 
Figure 12. A wide and rather shallow groove which 
is cut all around to receive the fin is shown at A, and 
the manner in which the faces of the dies are some¬ 
times sloped away for the same purpose is shown at 
B. Figure 13 show T s a forging of a lever which has 
the fin, X, still on it, and the trimming die, shown 
in the lower part of illustration, shears off the fin 
and leaves the forging clean and ready for use. 

Cylindrical work can be manipulated by the oper¬ 
ator so that no fin will be left by simply rotating the 
work under the hammer during the process of forg¬ 
ing. Drop-forged levers are frequently made with a 


DROP FORGING AND DIES 


29 



FIG. 12. DROP FORGE DIE WITH SPACE FOR RECEIVING FINS 


countersunk portion in the center of the bosses in 
order to facilitate machining, as shown in “A” of 
Figure 14. Other cases when the hole itself can be 
punched directly through the work are indicated in 
the dies shown at “B” in the same illustration. Oc¬ 
casionally the hole in the boss is taken care of by 
the method shown at “C”; this leaves a thin web 
at the center of the hole, which is afterwards punched 
out without difficulty. So many forms of dies and 
forgings for all classes of work occur that it is 
obviously out of the question to do more than out¬ 
line the simple form so as to give an approximation 
of the method of treatment. 

Blanking Dies.—When work is produced from cold 
metal the processes used for shaping the forms are 










30 


TOOLS AND PATTERNS 



FIG. 13. A ROUGH FORGING AND ITS TRIMMING DIE 


very different from those previously described under 
the head of drop forgings. Cutting dies should 
properly include all types which punch or cut out 
various shapes from the metal as it is fed through 
the press when the section of the metal itself is not 
changed to any extent. Shaping dies on the contrary 
include any which change the form of the metal from 
its original flat condition to one of a different con¬ 
tour in which the various surfaces are in different 
planes. Some dies of the latter class really constitute 
a combination of cutting and shaping dies—the work 
is first punched out to shape and is afterwards 
formed. 

Follow dies are dies which have two or more cut¬ 
ting portions acting progressively on the work as it 































DROP FORGING AND DIES 


31 



FIG. 14 . METHODS OF PROVIDING FOR HOLES IN DROP FORGINGS 


is fed through the press, each stroke producing a 
finished piece. Dies of this kind are sometimes called 
tandem dies. An example of this die is shown in 
Figure 15. It will he seen that the work “A” has 
three separate operations all performed upon it in 
the same die, and yet at each stroke of the press a 
completed piece is turned out. 

Gang dies, are often used for small parts in order 
to save waste metal and, at the same time, to produce 
work more rapidly. An example is shown in Figure 
16. This illustration shows that several pieces may 
he made at one stroke of the press with a compara¬ 
tively small amount of wasted metal. 

A compound die is one that is arranged in such a 
way that the punch and die portions are not separ¬ 
ated but are combined in such manner that the upper 

























32 


TOOLS AND PATTERNS 



and lower half each contain a punch and die. Such a 
die has its stripper springs adjusted so that they are 
strong enough to overcome the cutting resistance of 
the stock, after which they are compressed until the 
end of the stroke is reached. In a compound die all 
the operations are carried out synchronously while 
the stock is firmly held; therefore, the work pro¬ 
duced by this type of die is more accurate than those 
previously described. It is not as simple a die, how¬ 
ever, and it requires much more care in setting up. 

Forming dies are used for work of hollow form, a 
cavity being made in the die into which the work is 

















































DROP FORGING AND DIES 


33 


FIRST OPERATION 




o 1 

w 

w 



SECOND OPERATION 



DIE 


FIG. 16 . AN EXAMPLE OF A GANG DIE 


forced by the press. Drawing dies are used for much 
the same class of work as forming dies; but in the 
process of drawing, the flat blank which is being 
formed is held rigidly between the surfaces of the 
die so that wrinkles will not form during the draw¬ 
ing operation. Curling dies and bending dies are 
used respectively for turning over the edges of sheet 



























































34 


TOOLS AND PATTERNS 


metal pieces and for bending the surface of a piece 
of work into a partial curve, not, however, a com¬ 
plete circle. 

Sub-press dies, strictly speaking, are not a special 
class of die except in the sense that the punch and 
die are combined in a single unit by means of guides 
so that there is no necessity for lining up the lower 
and upper dies when setting up. A high degree of 
accuracy is assured when this class of die is used, 
although the expense of the die itself may be some¬ 
what greater. 


CHAPTER III 


DRILLING, BORING, AND REAMING 

Drills.—Drills may be considered as one of the 
most important factors in producing work in any 
manufacturing plant. A drill must not be considered 
as a finishing tool, however, although if is possible, 
if the drill is carefully ground and the work pain¬ 
stakingly performed, to produce a clean hole quite 
close to the size of the tool. For many classes of 
work a drilled hole answers every purpose, and if 
followed by a reamer a smooth hole of any required 
diameter may be readily produced. For bolts or 
other fastenings of similar character a drilled hole is 
usually considered commercially good. 

As in other types of tools, drill shapes and forms 
are dependent to a certain extent on the class of 
material upon which they are to be used. Almost 
any kind of a pointed tool will drill a hole if revolved 
under pressure, but in order to produce the work 
properly the drill shape must be suited to the material 
to be cut. As a preliminary operation in drilling a 
long hole, it is often advisable to spot the material 
with a short drill. The stiffness of the short tool is 
an advantage to start the hole in the right place and 
not run any chance of the deflection which might take 
place if a long drill were to be used first. Further- 
35 


36 


TOOLS AND PATTERNS 


more, a considerable saving in drill grinding will 
result, as the short drill gets through the scale on 
the work and leaves the long drill to take a clean 
cut under the surface of the scale. This treatment is 
of marked advantage in drilling forgings on the 
turret lathe. 

Drills in common use are shown in Figure 17. The 
spotting drill, A, is ground to an angle of 40 degrees 
in order that the following drill may commence its 
cut on the lips and not on the point; it will then cut 
more freely and get a better start in the work. The 
manner in which the cutting action takes place with 
the following drill is clearly shown in the diagram 
at B. 

The drill, C, is little used in general manufacturing, 



FIG. 17. VARIOUS TYPES OF DRILLS 



























DRILLING, BORING, FORGING 37 

but it is an important item in the equipment of the 
blacksmith or metal worker. A drill of this type is 
not suited to deep holes, although is particularly 
adapted to thin work. It has no twist, and there¬ 
fore does not have a tendency to tear and break the 
metal as it passes through the work. The wood drill, 
D, is often used by cabinet makers and other wood 
workers. This drill also has no twist, but is partly 
cylindrical with a groove for chips on each side. 

The ordinary type of twist drill, E, is used in 
general manufacturing work. The angle at which it 
is usually ground, indicated in the illustration, is 
about 31 degrees, but the angle of the twist cut varies 
in different makes; sometimes it is uniformly twisted 
throughought its length and again it may be made 
with, what is termed, an increase twist to give greater 
strength in a long drill. Twist drills were originally 
made by twisting up a piece of flat stock, but the 
present method of manufacture is to mill the helical 
grooves from a round bar of steel. A shank is pio- 
vided in order properly to hold the drill and drive 
it through the work, this portion being either straight 
or tapering. If straight it may be held in a drill 
chuck or in a plain bushing with set screws, but if 
the shank tapers, it is provided with a flatened end, 
or “tang,” which acts as a driver in the drill socket. 
A modern twist drill has a slight “back taper” run¬ 
ning longitudinally from point to shank so that it 
will work with more freedom. Body clearance is also 
provided as indicated in the end view of the tool 
shown in the illustration. The purpose of the two 
clearances is to avoid the heating of the drill by 


38 


TOOLS AND PATTERNS 


friction in the hole and also to make the cutting 
action easier. 

The cutting angles of the lip of the drill vary from 
59 to 76 degrees depending on the material which is 
to he drilled; ordinarily a drill for steel and iron is 
ground to 59 or 60 degrees, while for brass the angle 
may be around 75 degrees. It is of the greatest im¬ 
portance that drill angles should be equal, for unless 
this is the case the hole will be cut too large, as 
indicated at F, since the tool is working around a 
false center which is not the actual center of the 
drill stock itself. In such a case the longest lip 
governs the size of the hole, as may be readily seen. 

Another type of twist drill, G, is known as a flat 
twist drill. As made by some manufacturers it has 
a flat shank requiring a special form of socket for 
holding. The Pratt & Whitney Co. make the form 
illustrated in which an increase of twist is given to 
the shank portion to provide additional surface 
which is ground to fit the taper in a standard socket, 
thus doing away with the necessity for special sock¬ 
ets. The advantages claimed for this type of drill 
are that it has greater chip clearance and higher pro¬ 
ductive capacity. 

Core Drills.—When holes are to be drilled in cast 
iron or other cast metals in which the holes have 
been cored, another type of drill, often termed a “core 
drill,’’ is used. Drills of this kind, H, Figure 17, are 
listed by manufacturers as “three-groove chucking 
reamers.” It may be noted that the end of the drill 
does not come to a point, as in the case of the regular 
twist drill, but is blunted because it has no work to 


DRILLING, BORING, FORGING 


39 


do at the center. The three Antes tend to keep the 
tool in a central position while drilling. Four Antes 
instead of three are sometimes used. In the larger 
sizes shell drills, K, are found to he capable of very 
severe service. They are held on an arbor like a shell 
reamer and are generally four Auted. 

An important point in connection with the use of 
core drills is that any variation or eccentricity of the 
cored portion of the work is likely to affect the tool 
to a considerable extent so that the resulting hole is 
not true with the remainder of the work. This 
trouble can be easily avoided by truing up the hole 
for a short distance with a single-point tool before 
inserting the core drill, as indicated in Figure 18. 

Counterbores.—When a shouldered hole is to be 
made, such as that shown in Figure 19, the counter¬ 
bore is generally employed. In order to have the two 
holes concentric, two methods are possible: In one the 



FIG. 18 . STARTING A HOLE WITH A STARTING TOOL PRIOR 
TO THE USE OF A CORE DRILL 















40 


TOOLS AND PATTERNS 



work is revolved and the cutting tools are held 
rigidly without revolving; the holes can then be pro¬ 
duced by two or more cuts of the tools after they are 
set out to the required diameters. In the second 
method the work is stationary and the tools revolve; 
the smaller hole is usually made first and a tool called 
a counterbore, A, like that shown in Figure 19, hav¬ 
ing a pilot, B, which enters the smaller hole, does the 
remainder of the cutting on the larger diameter. It 
will be noted that the action of the pilot in the pre¬ 
viously drilled small hole tends to steady the action 
of the counterbore and produce a concentric hole. 

Several varieties of counterbores are in use, the 
principles of which are the same as that shown at 



























DRILLING, BORING, FORGING 41 

A. One type, D, has interchangeable blades or cut¬ 
ting lips and removable bushings, C, which allow 
work to be done in holes of various diameters. An¬ 
other type, E, also has a removable pilot, which can 
be provided with cutting heads of different diameters, 
but the pilot does not revolve. If work requiring a 
high degree of accuracy is intended, the type with a 
revolving pilot is advisable. Some cases occur when 
it may be possible to extend a pilot somewhat smaller 
than the hole, so that it can be guided in a bushing 
beyond the work itself. In either of these cases there 
is little danger of injury to the finished surface of the 
smaller hole. 



FIG. 20 . (a) hand reamer, (b) plain fluted chucking 

REAMER. (c) ROSE CHUCKING REAMER 


Reamers.—When a hole is to be accurately finished 
to a given diameter it may either be bored to this 
size by successive cuts of the boring tool or it may 
be reamed. A reamer, therefore, may be considered 
strictly as a tool for sizing a hole. Several types of 
reamers are in common use and the selection of the 
type for any particular work depends upon the ma- 







42 


TOOLS AND PATTERNS 


terial to be cut, the diameter of the work, and the 
previous operations which have been done upon it. 
As reamers are used entirely as finishing tools, the 
amount of metal which they remove is small and is 
dependent upon the diameter of the hole and the 
nature of the metal. 

A group of reamers of various types is shown in 
Figure 20; while the types here represented do not 
include every variety, they may be considered as rep¬ 
resentative. The simplest type in common use is the 
plain fluted hand reamer, shown at A, which has a 
squared end to which a wrench or holder can be ap¬ 
plied for the purpose of forcing the reamer through 
the hole. Reamers of this kind are sometimes made 
with spiral flutes. 

The plain chucking reamer, B, in the same illus¬ 
tration, is largely used in drill press or turret lathe 
work and is made with either a taper or straight 
shank. When used in turret-lathe work it is held in 
a floating holder, different types of which are de¬ 
scribed under their proper heading. The type of 
fluted chucking reamer shown at B may have the 
flutes equally spaced around the periphery of the 
reamer or they may be staggered so that no two tooth 
spacings are exactly alike. The object of this ar¬ 
rangement is to prevent “ chatter. ” 

Another type, called a rose chucking reamer, C, is 
intended for work of a fragile nature or for thin 
work which might be distorted in reaming with an 
ordinary coarse-fluted reamer. The rose reamer has 
wider “ lands’’ (space between indentations) and is 
not lipped like the chucking reamer previously men- 


DRILLING, BORING, FORGING 


43 



tioned. It should cut only on the end, and the ob¬ 
ject of the wide lands on the flutes is to preserve a 
bearing surface and thus tend to produce greater ac¬ 
curacy in the work. 

Inserted-Blade Reamers.—The simplest type of in- 
serted-blade reamer is the tool shown at A in Figure 
21. T kis reamer is never used with a floating holder, 
the design being such that the blade, b, floats in the 
holder, a. For certain classes of work, especially 
vertical work, as on a vertical boring mill, reamers 
of this type may be made to do excellent work. 
Upkeep is provided for by means of a tapered 
screw and a slot in the blade whereby the blade may 
be expanded and reground. On account of the cost 
of high-speed steel later developments in the de¬ 
sign of reamers favor the inserted-blade type so made 




































44 


TOOLS AND PATTERNS 


that the blades can be removed and replaced at a 
nominal expense. By this means the upkeep of the 
tool is quite low: a number of styles can be purchased 
in the American market. 

A good example is that shown at B in Figure 21, 
made by the Pratt & Whitney Co. In this type of 
reamer the body, d, is provided with tapered slots in 
which the blades, e, fit. The clamps, f, in the sec-, 
tional view, lock the blades by means of the screws 
shown. Various diameters within the capacity of the 
reamer can be readily made by manipulating the lock¬ 
ing nut shown at g. It is a very difficult matter to 
change a reamer adjustment of this kind in such a 
way that all the blades will cut equally, but it is a 
simple matter to regrind to the desired size after set¬ 
ting the blades slightly oversize to allow for the 
grinding. 

Another excellent type of inserted-blade reamer 
is shown in the same illustration at C. In this type 
the body of the tool is cut out, as indicated, to re¬ 
ceive the blades, h. It will be seen that these blades 
are so made that each forms two teeth, and are held 
in place by the screws shown. When a reamer of this 
kind becomes worn so that it does not size the work 
properly, the blades may be removed and strips of 
paper inserted under them, after which they can be 
reground to the desired size. 

Taper Reamers.—Before reaming a tapering hole, 
the first essential is that the bored hole be true and 
straight. When the taper is very “shallow’’—i.e., 
the angle of the taper very slight—a single reamer 
can be used, as, for instance, in making a taper pin 


DRILLING, BORING, FORGING 


45 



FIG. 22 . TYPES OF TAPER REAMERS 


hole; but when a more obtuse angle is required sev¬ 
eral tools may be necessary to produce the final taper. 
For this latter work the first two reamers may be 
made as indicated, in Figure 22, at A and B. In the 
tool, A, the flutes are cut straight but are threaded or 
nicked to “break the chip” and make the cutting ac¬ 
tion easier. In order to overcome the tendency to¬ 
ward “drawing in,” a slight left-hand spiral may be 
given to the flutes, the angle of the spiral being de¬ 
pendent somewhat on the angularity of the tapered 
hole. It is also advisable in some cases to space the 
teeth unequally to avoid chatter which is more likely 
to occur in taper than in straight reaming. Taper 
reamers should be made longer than the holes in 
which they are to be used in order to provide for up¬ 
keep. Roughing reamers should have fewer flutes 
than the finishing tool for greater chip clearance. 


























46 


TOOLS AND PATTERNS 


Taper reamers are occasionally made for large 
work with a single inserted blade, such as that 
shown at C in the illustration. A tool of this kind 
is not, strictly speaking, a reamer, but is more 
nearly a scraping tool. This type of tool is valu¬ 
able for some classes of work, however, as it can be 
adjusted to size very readily and can be reground 
a number of times. 



Boring Tools.—The engine lathe is generally used 
when a hole is to be bored in but one piece of work 
which can be revolved. The type of boring tool used 
for small holes under these conditions is shown in 
Figure 23 at A. Due to its construction, a tool of 
this kind is only suited to very light work, and a 
number of cuts must be taken to bring the work 
to the required size. As such tools are seldom used 
to any great extent in manufacturing work, it is 



































DRILLING, BORING, FORGING 47 

unnecessary to mention their shortcomings. They 
serve the purpose for which they are intended 
boring holes in jigs and the like, and therefore 
need no further comment. Tools of a similar char¬ 
acter but somewhat heavier are occasionally used 
in turret lathe work for boring short holes, al¬ 
though a boring bar is generally used when the 
size of the hole will permit. When a boring tool 
of this type must be used for manufacturing work, 
it is better to make it in the form shown at B in 
the illustration. It will be seen that this tool has 
a more substantial nose and that it is ground to 
a different shape than the toolmaker’s tool shown at 
A in the illustration. It will give very good results 
on short work. 

When a turret lathe must be used to bore a hole 
and the size of the hole will permit, it is better to 
use a bar such as that shown at A in Figure 24. 
Single-point tools, or tools having but one cutting 
edge, will produce more accurate work than multiple¬ 
cutting tools, although they will not turn out the 
work as rapidly. The bar, B, made in a variety of 
ways to suit different conditions, is used in many 
classes of work. The tool, placed straight across the 
bar, is held with a set screw or a taper pin, and may 
or may not have the added refinement of a backing- 
up screw to make adjustment easier. The bar may 
be piloted in a bushing of some kind, or it may be as 
shown in the figure. If several diameters are to be 
machined at the same time a multiple bar, C, can be 
used to good advantage, the general points in con¬ 
struction being much the same. 


48 


TOOLS AND PATTERNS 


Flat-Cutter Boring’ Bars.—For rapid production 
flat cutters are frequently used in bars sucli as shown 
at D, Figure 24. The advantage obtained by the 
use of two cutting edges is that the amount of work 
performed by each cutter is less than with a single¬ 
point tool, and therefore the feed can be somewhat 
increased. The disadvantage lies in the fact that 
diameter sizes are soon lost on account of re-grind¬ 
ing, while the single point tool can be re-set to a 
given diameter a number of times through a simple 
adjustment. 

For very heavy cutting a cutter head is made up 
similar to that shown at E in the illustration. In 
boring automobile cylinders, or other work of similar 
character, tools of this kind can be used to advan¬ 
tage, but it is highly important to have all the cutting 
points ground to the same diameter and angle so that 
they will do an equal amount of work. Bars of other 
varieties besides those shown are used in general 
manufacturing, but the working principles are much 
the same as the ones described. 

Adjustable Boring Tool for Tool-Room Work.—The 
requirements of the toolmaker are somewhat differ¬ 
ent from the requirements in the manufacturing de¬ 
partments. Therefore the type of boring tool which 
he is likely to favor will differ from those previously 
described and may take the form of that shown in 
Figure 25. This tool will probably be provided with 
a taper shank, A, which will fit the tailstock of the 
lathe. The cutting tool itself is small and is held by 
two screws, as shown, in the swinging block pivoted 
at B in the body of the toolholder- The two screws, 


DRILLING, BORING, FORGING 


49 


Work 




J o 




FIG. 24. VARIOUS TYPES OF BORING BARS 












































50 


TOOLS AND PATTERNS 



FIG. 25. toolmakers’ adjustable boring tool 


C, C, are used for adjustment, one being loosened 
and the opposite one tightened until the desired 
diameter is obtained. Other varieties of this tool 
may be found in any manufacturers tool room. A 
toolmaker will often have one of his own make 
which is of course “superior to all others.’’ For 
boring bushing holes in jigs, tools of this sort are 
almost indispensable. 

Recessing Tools.—In turret lathe work it is often 
necessary to produce a recess or groove in the in¬ 
side of the work. When the work is of medium 
size, so that a good-sized tool can be used, no par¬ 
ticular difficulty is experienced, for the work can be 
done by a number of different methods. If the work 
is done on an engine lathe, a tool may be conven¬ 
iently held on the cross slide of the lathe, as indi¬ 
cated at A, Figure 26, and the carriage can be with¬ 
drawn until the tool has reached the proper depth, 
after which it can be fed along the distance re- 




























DRILLING, BORING, FORGING 


51 



FIG. 26 . A SIMPLE RECESSING TOOL ON AN ENGINE LATHE 

quired to produce the work, as shown at B. It must 
be remembered, however, that many varieties of tur¬ 
ret lathes do not have a cross-sliding movement to 
the turret, nor does the cross slide in some other 
varieties have a longitudinal power feed. _ Hence, it 
is necessary to design a recessing tool in such a 
way that it will be self-contained and have its own 
moving parts, irrespective of the turret movement. 

Much depends upon the nature of the groove to 
be cut. If it is narrow, such as that shown in Fig¬ 
ure 27, it is easily possible to build a tool of a very 
simple character to be operated by the workman. 
In this case the tool consists simply of a body, A, 
in which the holder, B, is set eccentrically to the 
center line of the spindle and at a sufficient distance 
to give the depth of cut desired. The handle, C, 
furnishes the necessary feed. 

When a recess is cut deeply into the work', and 






































52 


TOOLS AND PATTERNS 



FIG. 27 . SIMPLE RECESSING TOOL FOR TURRET LATHE WORK 



FIG. 28 . RECESSING TOOL FOR TURRET LATHE 

































































































































DRILLING, BORING, FORGING 53 

when the tool extends a considerable distance from 
the turret face, a scheme such as that indicated in 
Figure 28 can be utilized to good advantage. In 
this case the body of the tool, A, is mounted on the 
turret and contains a sliding member, B, in which 
is mounted the recessing bar, C, having a tool at 
Assuming that there are tools on the front 
of the cross side, which are used in connection with 
the work, and that the rear of the slide is supplied 
with a support, E, by means of which the recessing 
bar is supported and fed into the work by with¬ 
drawal of the cross slide; it will be seen, then, that 
a movement of the slide will carry the tool into the 
work as deeply as permitted by the stop screw, F. 
The slide carrying the recessing bar is controlled by 
a spring, so that when the feeding pressure is re¬ 
leased the spring will return the slide to its normal 
position. 

Extraordinary cases occur occasionally in ma¬ 
chine shop practice when a number of parts must be 
made which call for more elaborate tooling than is 
ordinarily required. An example of this sort is 
shown in Figure 29. In this case, the work, A, is 
a steel casing with two recesses equidistant from the 
center line as shown at B. The work is of large size 
and requires a 20-inch swing turret lathe to handle 
it. It will be seen that the two recesses are in such 
positions that they can not readily be machined. As 
a support for any tool making this cut is necessary, a 
bushing has been inserted in the fixture to hold the 
piece so that a pilot can be used on the bar for re¬ 
cessing. This bar has been drilled to receive a rod, 


54 


TOOLS AND PATTERNS 



FIG. 29. AN ELABORATE RECESSING TOOL FOR A LARGE 
STEEL CASING 


C, on which two angular splines have been cut. The 
splines engage with the two small tool blocks, D, 
which hold the recessing tools. The mechanism is 
operated by means of a pinion, E, which engages 
with a rack cut on the operating bar, as clearly indi¬ 
cated in the illustration. 

It is obvious that any tool of this kind would not 
be built unless very many pieces were to be ma¬ 
chined, as it would not prove economical otherwise 
because of the high first cost. For the work shown, 
however, some thousands of pieces were to be made, 
and the elaborate equipment paid for itself many times 
over in the saving of time and in the accuracy of pro¬ 
duction. As the depth of the recess on this piece was 
rather important, it was essential that the spacing of 
the grooves should be symmetrical about the center 
line, which also made the tool so much more essential. 























































CHAPTER IV 


TURNING, FORMING, AND THREADING 

Hollow Mills.—In roughing-down bar stock similar 
to the piece shown at A in Figure 30, a hollow mill is 
frequently used, but this type of tool is not to be 
recommended for accuracy. But as it has several 
cutting lips it will remove stock rapidly and can be 
used for roughing operations to good advantage. 
The ring, B, is used to prevent the lips of the tool 
from springing and also to make small adjustments 
by drawinig in the lips to a slightly smaller diameter 
when necessary, but the adjustment obtainable on 
this type of hollow mill amounts to only a few thou¬ 
sandths of an inch. An adjustable type such as shown 
at C, is much more expensive but possesses some ad¬ 
vantages. The cutting tools, D, D, are of the in¬ 
serted type and are controlled as to their diameter by 
a ring with cams cut upon it which engage with the 
cutting tools and force them in or out as desired. 
Although a tool of this type can be more accurately 
adjusted to a given diameter than the one previously 
described, it will not remove stock in as great a 
quantity nor has it the desirable features of chip 
clearance that the former tool possesses. 

Another type of hollow mill designed for excep¬ 
tionally heavy cutting and large stock reduction is 
55 


56 


TOOLS AND PATTERNS 



shown at E. This tool is of special character and is 
designed for a single purpose. It will be noticed, 
however, that the cutting tools, F, are adjustable and 
that they are heavy in section so as to carry away 
heat rapidly. Tools of this sort are designed only 
for the most severe service and are not economical 










































TURNING, FORMING, THREADING 57 

unless stock reductions are large and a great number 
of pieces of the same character are to be machined. 
An important point in connection with all hollow 
mills is the back clearance which, on the type shown 
at A should be at least an eighth of an inch to the 
foot. The cutting edges of hollow mills should be a 
trifle ahead of the center for steel work but on center 
for brass. 

Turning Tools. —On turret lathe work tools used 
for turning are made up in a different way from 
those employed on the engine lathe. On the engine 
lathe the tools are held on the cross slide of the ma¬ 
chine in suitably designed tool holders, while in tur¬ 
ret lathe.work the holders are mounted on the turret 
and the tools are held either horizontally or ver¬ 
tically. One of the simplest types of turning tool is 
shown in Figure 31, the holders in this case being 



FIG. 31. A SIMPLE FORMING TOOL FOR TURRET LATHE WORK 






















58 


TOOLS AND PATTERNS 


made of east, iron and bolted to the turret face. The 
tool is set at an angle and is held in place by two set 
screws. Adjustments for diameters can be readily 
made within the capacity of the tool. For short 
lengths and small diameters, a tool of this kind will 
give excellent results; but when the work is long, as 
in the turning of bar work on a screw machine, it is 
necessary to provide support for the work opposite to 
the cutting point of the tool. 

A simple type of tool for this latter purpose, usu¬ 
ally termed “box tool”, is shown in Figure 32. The 



FIG. 32. A SIMPLE BOX TOOL FOR TURRET LATHE WORK 


tool is mounted in a block opposite to which a V- 
shaped supporting block is so placed that it can be 
adjusted to the diameter of the work being cut. 
Makers of turret lathes have developed a great va¬ 
riety of tools along these lines to suit the particular 
machine which they manufacture. For small screw- 
machine work, box tools with two or more adjustable 
blocks are frequently made which are extremely use¬ 
ful for automatic and light hand-screw machine work. 

Adjustable Turning Tools.— For bar work it is very 
desirable to have tools which can be adjusted rapidly 































TURNING, FORMING, THREADING 


59 



FIG. 33. ADJUSTABLE TURNING TOOL WITH ROLLER BACK RESTS 
Pratt & Whitney Co. 


to various diameters within their capacity, and on 
turret lathe work several tools of the styles shown 
in Figure 33 may be mounted on the turret and con¬ 
trol several diameters on the bar. Such tools are 
made with both roller-back and V-back rests, the 
back rests being adjustably mounted so that they can 
be used either for following or leading. When used 
as following back rests, they are set to the diameter 
at which the tool is at work and slightly behind a 
point opposite the cutting tool. When used as lead¬ 
ing back rests, the material must either be bright 
rolled steel or it must have been finished to a given 
diameter in a previous operation. Leading back rests 
can never be used on rough stock; but following back 
rests, as they work directly behind a surface which 
has just been finished, are always used in rough 
stock turning. The difference between the use of the 








60 


TOOLS AND PATTERNS 


V-back rest and the roller-back rest is that the rollers 
are less likely to mar the work, while V-back rests 
may cause slight abrasions, especially if work is done 
at high speed. However, on automatic work of small 
diameter the V-rests are commonly used with per¬ 
fectly satisfactory result. 

Open-side Turning Tools.—The tool shown in Fig¬ 
ure 34 is used for turning short lengths when the 



FIG. 34. OPEN SIDE TURNING TOOL 
Pratt & Whitney Co. 


work is held rigidly; therefore it does not require 
back rest support. A tool of this nature is adjustable 
to different diameters within its capacity, and some¬ 
times possesses an added refinement in an adjustable 
stop or an index on the screw so that it can be set 
for different diameters for both roughing and finish¬ 
ing cuts. 

Overhead Turning Tools.—It is important that any 
type of turning tool should be held rigidly to avoid 










TURNING, FORMING, THREADING 


61 



FIG. 35. SPECIAL PILOTED TURNING TOOL FOR RAPID PRODUCTION 


the chatter resulting from excessive vibration. For 
this reason turret lathe tools for heavy classes of 
work—such as castings, forgings, and the like— 
should be so constructed that they will have ample 
section to withstand cutting strains without spring¬ 
ing away from the work. For manufacturing work 
in large quantities, special tools are frequently built 
such as that shown in Figure 35 at A. It will be seen 
that this tool is mounted on the turret of the turret 












































































62 


TOOLS AND PATTERNS 


lathe and has additional support from the pilot bar, 
B, which enters a bushing in a bracket on the head 
stock of the machine. The several tools are remov¬ 
able and adjustable, so that they can be replaced and 
reground when necessary. Such tools are not in¬ 
tended for universal use but are specially designed to 
meet the requirements of a particular case. It is al¬ 
ways advisable, in making up a tool of this kind, 
however, to provide as much latitude as possible, so 
that in the. event of a change in design the tool can 
still be used with slight modifications. 

Turning Tools for Vertical Boring Mills.—Many 
people do not consider that the vertical boring mill is 
sufficiently adaptable to handle special classes of 
manufacturing work to good advantage, but its 
power and stability are such that, if properly tooled, 
it will prove a valuable manufacturing machine. The 
majority of boring mills in use throughout the coun¬ 
try are not run anywhere near to their maximum effi¬ 
ciency. Only a short time ago, while investigating 
conditions in an old factory, I discovered three bor¬ 
ing mills at work continuously, yet only turning 
out about one-fifth of the product which they should 
have accomplished. When the Superintendent was 
asked Why these machines seemed to be such small 
producers, he informed me that they turned the work 
out “as fast as the assembling room could use it,” 
so he had no fault to find. 

The multiple turning tool head shown in Figure 
36 gives an idea of the adaptability of multiple tools 
to a vertical boring mill when the product is suffi¬ 
ciently large to warrant a little expenditure for tools. 


TURNING, FORMING, THREADING 


63 



FIG. 36. SPECIAL TURNING TOOLS ON A VERTICAL BORING MILL 


In this case the heavy tool holder, A, contains three 
tools, B, C, and D, which all work simultaneously on 
the casting. At the same time the two tools, E, and 
F, in the left-hand head are at work facing the sur¬ 
faces indicated. It is unnecessary to go into the mat¬ 
ter of turning tools on the vertical boring mill to any 
great extent as the more modern machines used in 
manufacturing are provided with a side head in ad¬ 
dition to a turret, each containing a number of tools. 
When a machine of this type is used, the side head 
provides a means of setting up four or more tools to 
be operated in sequence, and adjustment of the side 
head permits diameter settings to be easily made. 
























































64 


TOOLS AND PATTERNS 


Cutting-off Tools. —The ordinary type of tool used 
for cutting off work which has been previously turned 
or formed is shown in Figure 37 at A. Such tools, 
however, are uneconomical, for after grinding a few 
times, they must be annealed and reforged, or drawn 
out to their former length. The inserted-blade type 



of cutting-off tool, shown at B in the same illustra¬ 
tion, is much more economical, for it is so designed 
that the blade, C, can be clamped securely in the 
holder and adjusted to any desired position without 
difficulty. The holder is so made that it will fit sev¬ 
eral different sizes of tool posts, thereby making its 
adaptability to different classes of work and different 
machines so much the greater. In the holder shown, 
the blades can be bought ready-made to slip into the 
holders, and only require an occasional grinding to 
keep them in condition. 































TURNING, FORMING, THREADING 


65 


Threading Tools. —The simplest form of threading 
tools is the forged tool shown at A in Figure 38. 
Such a tool is used for plain threading on the engine 
lathe and needs no particular comment as the nature 
of the operation is so well known. In any threading 



FIG. 38. THE SIMPLEST FORM OF THREADING TOOL 


tool there are two essential points; first the correct 
shape of the tool itself, and second, its setting in re¬ 
lation to the work. If a threading tool is ground to 
the correct angle on its sides and is set on the center 
of the work, it should produce a threaded form of the 
correct angle. If, however, it does not come into 
contact with the work at the proper point, and if the 
cutting face is tipped one way or the other to bring 
the point on center, the resulting angle of thread will 
not he correct. 

Because of these facts, it is evident that the great¬ 
est care must he exercised both in grinding and in 
setting any sort of threading tool. In turret lathe 
work, threading tools of the single-point variety can 
not he used unless the machine is provided with a 


























66 


TOOLS AND PATTERNS 


thread-chasing attachment whereby the lead of the 
screw can be properly controlled. There are many 
cases, however, when such an attachment is a great 
advantage, and it is in cases of this kind that a spe¬ 
cial design of cutting tool is desirable. When the 
thread-chasing attachment is applied to the cross 
slide of the machine, an ordinary type of tool may 
be used for the work if desired; but when the thread¬ 
ing attachment affects the turret slide, another type 
of tool may be found necessary. 

If the work calls for an interior thread, a bar, such 
as that shown at A in Figure 39, can be used with 
a tool of the single-point type, as B, or of the chaser 



FIG. 39. TYPES OF THREAD CHASING TOOLS 























TURNING, FORMING, THREADING 67 

type, as C. This bar must be held in a special 
holder on the turret, which provides for quick with¬ 
drawal and a micrometer stop for depth. A tool slide 
of this sort can be easily applied to the turret of the 
machine and presents no great difficulty in the mat¬ 
ter of design. When the turret itself has cross-slid¬ 
ing features and a micrometer dial adjustment, there 
is no necessity for an extra tool holder of the type 
mentioned. 

Goose Neck Threading Tool. —Due to the peculiar 
construction of a threading tool it is very likely to 
chatter under the cut. As chatter is caused by a 
rapidly repeated springing away of the tool from the 
work and by an equally repeated digging in again, 
both tool and work should be held so rigidly that 
such vibration will not be possible. Such a condition 
is difficult to obtain, however, and therefore the tool 
may be so constructed that it will never have a 
tendency to dig in. A special tool of this nature, 
made especially for threading work on the turret 



1TIG. 40 . A GOOSE-NECK THREADING TOOL FOR TURRET LATHE 































68 


TOOLS AND PATTERNS 


lathe, is shown in Figure 40. The tool-holder body 
is mounted on the bar, A, which is held in the tur¬ 
ret of the machine. The body is drilled at B and 
slotted at C to allow for springing action. The 
threading tool, D, is locked in position and is ground 
to the correct angle for threading. In use, the posi¬ 
tion of the spring hinge allows the tool to spring 
away from the work without digging in. 

Forming Tools. —When it becomes necessary to 
machine a form a number of more or less irregular 
shapes on an engine lathe, turret lathe, or other ma¬ 
chine of similar character, a forming tool of some 
sort is indispensible. When only a single piece is to 
be made, the operator can work out the shape a little 
at a time on an engine lathe to fit a templet of sheet 
steel which has been carefully laid out to the re¬ 
quired dimensions. 

There are many kinds of forming tools whose utility 
depends to a great extent on the class of work for 
which they are intended, as well as the number of 
pieces which are to be machined and the accuracy 
required in the finished product. The type of tool 
selected for any given piece of work, therefore, should 
be determined by these factors. For example, in the 
work shown at the upper part of Figure 41, a simple 
angular groove is to be cut on a lot of 500 pieces. 
It would be inadvisable, therefore, to go to any great 
expense in the matter of a forming tool. A rect¬ 
angular tool, A, of some standard section should be 
formed to the shape shown at B with very little ex¬ 
pense or trouble, and the work may be produced 
without difficulty. If such a tool as this, however, 


TURNING, FORMING, THREADING 


69 



FIG. 41. THREE TYPES OF SIMPLE FORMING TOOLS 













































70 


TOOLS AND PATTERNS 


were to be used day after day and week after week, 
it would not give good results. Frequent regrinding 
would change the shape and size so that it would 
soon need to be replaced by another. This is due 
to the fact that the clearance as indicated by the 
dotted line is increasingly smaller than the part of 
the tool doing the cutting, so that as the face is 
ground away the tool becomes narrower and does 
not cut a groove of the desired width. To avoid 
changes in form caused by regrinding, an angularly 
set forming tool, such as that shown at C in the 
center of Figure 41 can be used to advantage. In 
this case a holder F, of special form is provided 
on the cross slide of the machine, bolted down in 
some approved manner according to the form of slide 
on which it is used. The holder is dovetailed at 
E to receive the forming tool on which the correct 
form, C, has been fashioned. The design of the tool 
is such that when it is ground flat across the front 
it will produce the required form. Clearance is taken 
care of by the angle at which the tool is set in the 
holder. Suitable clamping screws are provided in the 
holder so that as re-grinding is done adjustment can 
be made to keep the cutting edge always at the center 
line. In a tool of this character, which is required 
for very wide forms and heavy cutting, a set screw 
is sometimes placed in the holder directly under the 
tool to provide a firm support and take the thrust 
of the cut. When such provision is not made it 
may be found necessary to “shim” up the tool to 
prevent it from pushing down under the pressure of 
the cut. Tools of this kind are largely used on 


TURNING, FORMING, THREADING 71 

turret lathe and screw machine work for producing 
various form and shapes up to four or five inches 
in length. 

Smaller work, such as that on automatic and 
small hand-screw machines can he handled to ad¬ 
vantage with the circular type of forming tool, H, 
shown in the lower part of Figure 41. This type 
is tapped out to receive a screw which passes 
through a special tool holder on the cross slide of 
the machine. If the holder is made for the rear of 
the cross slide, the center line of the screw, K, is 
from i/s- to 14-inch below the center of the work. 
When the holder is designed to be used on the front 
of the cross slide, the center is about an equal 
amount above the work center, as indicated in the 
illustration. This arrangement is for the purpose of 
giving a greater clearance to the tool. It will be 
seen that a tool of this sort can be ground a great 
number of times and still preserve its form. Further¬ 
more, it is a type not difficult to make, as it can be 
turned on an engine lathe to the desired form and 
then cut out, as at M, to give the cutting lip. Since 
the cutting edge of the tool is not on the center on 
which the turning of the tool is accomplished, a 
suitable allowance for this difference must be made 
when shaping it. Formulas for this type of tool 
can be found in “Machinery’s Handbook.” 


CHAPTER V 


MILLING AND PLANING 

Milling Processes. —The process of milling a sur¬ 
face or form consists, essentially, in holding the 
work to he milled firmly and pushing it against 
a revolving cutter which removes the stock at a 
very rapid rate. The cutter is held in some ap¬ 
proved manner in the spindle of a milling machine, 
or on an arbor, either in a vertical or horizontal 
position depending upon the nature of the work 
and the type of machine to which it is applied. 
Milling machines are of several fundamental types, 
each possessing features more or less distinctive 
according to the manufacturer and the particular 
class of work for which the machine is intended. 
Thus we have hand milling machines, plain milling 
machines, the Lincoln type of milling machines, uni¬ 
versal milling machines, and so on, all of which are 
built with a horizontal spindle. Then there are 
vertical, rotary table, multiple spindle, duplex, and 
continuous milling machines, some of which have 
vertical spindles while others have horizontal spin¬ 
dles or even a combination of horizontal and verti¬ 
cal spindles on the same machine. In fact, the 
ramifications in these machines are somewhat diffi¬ 
cult to keep in touch with from day to day on ac- 
72 


MILLING AND PLANING 


73 


count of the many developments in rapid produc¬ 
tion processes. 

Factors Influencing Machine Selection. —When 
any piece of work is to he machined by milling 
processes the proper machine to produce it most eco¬ 
nomically must first be determined. Next, having de¬ 
termined the machine to use, the method of holding 
the work must be considered and a fixture designed 
for it; finally the type of cutter to be used must be 
decided upon. Several factors have an influence on 
these points and are of great importance. They in¬ 
clude : 

1. Nature and composition of the material to be 
cut. 

2. Size of the work. 

3. Amount of metal to be removed. 

4. Accuracy required. 

5. Width and shape of cut. 

6. Number of pieces to be machined. 

It is obvious in considering the nature and com¬ 
position of the material to be cut that for instance, 
a heavy piece of alloy steel would require a powerful 
machine in order to remove the stock to the best 
advantage, while a light piece of aluminum or brass 
could be handled more economically on a hand-feed 
or plain machine. 

The size of the work also has an effect on the ma¬ 
chine to be used, for it not infrequently happens 
that a light piece of work of large size must be 
machined on a heavy machine solely on account of 
the range required. In machining heavy forgings 


74 


TOOLS AND PATTEKNS 


of alloy steel, milling machines of great power must 
be used, and the fixtures in which the work is held 
must be of the most massive design in order to hold 
the work securely and prevent vibration or chatter. 

The amount of metal to be removed affects the 
selection of the machine tool on account of the 
power needed to pull the cut. At the same time 
it influences the design and form of the milling cutter 
adapted to the work. 

Speaking generally, surfacing cuts on castings are 
best handled by a face mill or end-milling cutter ar¬ 
ranged to cut either horizontally along the side of 
the work, if used on a horizontal milling machine, or 
vertically on top of the work if used on a vertical- 
spindle machine. Steel work, on the contrary, can 
more profitably be handled with a spiral milling 
cutter, the cut being taken in a direction parallel 
with the center line of the axis of rotation. The 
accuracy with which a piece of work must be finished 
determines whether a single roughing cut will be suffi¬ 
cient or whether both roughing and finishing cuts must 
be taken. For the general run of work which does not 
require a high degree of accuracy, a single cut may be 
taken with success, but when interchangeable work 
within close limits of accuracy is to be manufactured 
it is usually advisable to take two cuts. 

The width and shape of the cut determine both the 
class of machine to be used, the kind of cutters neces¬ 
sary, and the fixture required. In modern practice, a 
milling machine having both vertical and horizontal 
spindles is often selected for a piece of work of large 
size and the fixtures are designed so that several pieces 


MILLING AND PLANING 


75 


may be machined simultaneously. There are machines 
on the American market today having as many as 
seven spindles, all of which may be working simul¬ 
taneously on a certain piece of work. Furthermore, 
the work may be roughed and finished in the same 
machine, one “bank” of cutters serving for the rough¬ 
ing cuts and the others for the finishing operations. 
Obviously, machines of this character are very expen¬ 
sive, but for high production work they are great 
money savers. Here it will be seen that the number 
of pieces to be machined is an important factor in 
regard to the type of machine used. Another point 
in this connection which should not be overlooked is 
the type of fixture which is used, but—this matter 
will be dealt with in greater detail under a later head¬ 
ing. 

Milling Cutters. —The milling cutter, A, Figure 42, 
is an end mill of the ordinary variety with straight 
flutes. This type of cutter can be used for milling 
the edges of a surface on either a vertical or hori¬ 
zontal machine, and is provided with a taper shank 
to fit the milling machine spindle. The form, B, is 
of the center-cut type. It can be fed directly into the 
work if necessary, the teeth being so cut on the end 
as to permit this. With the type A, the form of 
tooth on the end does not permit such a cut to be 
taken. 

The cutter, C, is an end mill of the same general 
type as that shown at A, except that the flutes are 
cut spirally. The cutting action on the side of this 
mill is better than that on the straight fluted mill, A, 
because the entire width of the flute is not all in 


76 


TOOLS AND PATTERNS 



E 


FIG. 42. GROUP OF STRAIGHT-FLUTE, SPIRAL, AND SHELL 
END MILLS 

contact with the work at one time. The action, there¬ 
fore, is a shearing cut instead of a pushing cut. This 
mill, also, requires less power to drive it and is less 
likely to produce chatter. 













MILLING AND PLANING 


77 


The special form of cutter shown at D is made on 
the same principle as that shown at C, except that it 
is intended to cut only on the side. The spiral in 
this case is much more abrupt, so that the shearing 
action is very pronounced. A cutter of this kind 
gives excellent results on steel and produces a su¬ 
perior finish by virtue of its shearing cut. The flutes 
may be nicked to break the chip; this makes the cut¬ 
ting action easier and is an advantage on very tough 
and wiry material. 

When an end mill of a greater size is required, it 
is evident that it would not be economical to make 
both tool and shank of high speed steel; hence the 
shell end mill, E, has been devised. It can be seen 
that such a mill is easily attached to a stem or taper¬ 
ing arbor which fits the conical hole in the mill. The 
end of the arbor is threaded so that the mill can be 
forced back onto the taper by means of a nut applied 
to its face. 

Shell end mills are made in a variety of ways to 
suit different conditions; in the larger sizes, for in¬ 
stance, the body of the tool may be made of cast iron 
or steel with the cutter blades inserted. When in¬ 
serted blades are used it is evident that the cost of 
upkeep is much less than when the mill is cut from 
the solid metal, for a broken tooth can be readily 
replaced with a new one; furthermore, an entirely 
new set of blades can be substituted for a worn out 
set at comparatively small expense. Ordinarily, mills 
up to five inches in diameter are made from a single; 
piece of high-speed or carbon steel, while those above! 
this size are made with inserted blades. 


78 


TOOLS AND PATTERNS 


Slotting Cutters. —If a straight slot, open at the 
ends, is to be cut in a casting or other piece of work, 
a plain end mill such as that shown in Figure 42 at 
A or B can be used. But if the slot is I-shaped, 
another type of cutter, A, Figure 43, must be used. 



fig. 43. (a) tee-slot cutter, (b) fishtail cutter 
(c) two-lip slotting cutter 


This cutter is commonly spoken of as a tee-slot cut¬ 
ter. It will be noted that the neck of the tool is 
smaller than the cutter, so as to permit under cut¬ 
ting the work, or getting the tool down into a slot, 
etc. This same type of cutter is also used for cutting 
the circular slot in a shaft when a Woodruff key is 
to be inserted. 

In many kinds of manufacturing work it is neces¬ 
sary to cut a narrow slot with rounded ends, as for 
example a slot, or “spline’’ as it is more frequently 
called, in a shaft in which a key of rectangular sec¬ 
tion is to be fastened to act as a driver for a pulley 
or a gear. There are several ways to cut such a 










MILLING AND PLANING 


79 


spline, but such cutters as shown at B or C, Figure 
43, are most useful. The cutter, B, is termed a fish¬ 
tail cutter from its resemblance to a fish’s tail. The 
cutter, 0, is a two-lip slotting cutter or routing cut¬ 
ter. Both types are used for the same work, but the 
latter is used more frequently on cast iron to cut 
directly into a piece of work to the depth desired; 
then the work is fed along to the required distance. 
The fishtail type is more useful for steel work since 
it has better chip clearance. These tools are com¬ 
monly used on the spline-milling machine or on a 
milling machine with a spline-milling attachment for 
cutting slots and splines in general manufacturing 
work. 

Angular and Special Cutters— Various types of 
cutters have been developed for different kinds of 
work, the shapes being dependent upon the form to 
be cut and the manufacturing conditions governing 
the production. In making up reamers, drills, and 
special tools of different kinds, special cutters are a 
necessity in developing the required forms. Refer¬ 
ring to Figure 44, the sectional views shown at A and 
B indicate respectively the shape of the cutting edges 
of the milling cutters used for cutting flutes in 
reamers and taps. C and D are used for fluting twist 
drills and other work of similar character. F and G 
are respectively single and double angle cutters used 
largely for cutting spiral mills or other work when 
one or more of the surfaces to be milled lies at an 
angle to the axis of the work. E, H, and K are cor¬ 
nering, concave, and convex cutters respectively. 
They are used for a variety of purposes on special 


80 


TOOLS AND PATTERNS 



FIG. 44. ANGULAR AND SPECIAL TYPES OF MILLING CUTTERS 


work, the radii of the cutters being made up to suit 
any particular piece of work for which they are to 
be used. 

When a piece of work is to be machined which 
does not permit a cutter to be held on an arbor ex¬ 
tending on both sides of the cutter, it may be neces¬ 
sary to make up the types shown at L and M. It 
is obvious that as such a cutter must be screwed on 
to an arbor, as indicated, it must have either a right- 
hand or left-hand thread according to the direction 
of rotation of the spindle. These cutters can be made 
up in any form to suit the class of work on which 
they are to be used. 











MILLING AND PLANING 


81 



FIG. 45 . GEAR-TOOTH CUTTERS AND FORMED CUTTERS 


Gear-Tooth and Formed Cutters.—In cutting the 
teeth in spur gears the cutter, A, Figure 45, is fre¬ 
quently employed. This cutter, patented by Gould & 
Eberhardt, Newark, N. J., is so made that each tooth 
is of slightly different form than the one preceding 
it and progressively removes metal left by the pre¬ 
ceding tooth. The value of this method of cutting 
lies in the fact that the stock as it is removed is 
broken up into a great number of small chips instead 
of a comparatively small number of wide chips. 













82 


TOOLS AND PATTERNS 


The obvious advantage is that the cutting action is 
much easier and it requires less power than other 
forms of cutters. With this type, used for roughing 
only, the gear tooth is cut to its correct shape, leav¬ 
ing only a small amount to be removed by the finish¬ 
ing cutter, as shown at B in the illustration. The 
manner by which the chip is broken up by the cutter 
is indicated at C. The ordinary type of roughing-out 
or stocking cutter for gear teeth is of somewhat 
similar shape, but it makes a cut like that shown at 
D, Figure 45, which, it will be seen does not leave 
an equal amount of stock all around for the finishing 
cutter to remove, for this reason it is not as effective 
in its work as the other type. 

In some manufacturing work unusual shapes may 
be required cut from a flat surface or strip of metal, 
and when the quantity demanded is sufficient to war¬ 
rant it the form can be milled to advantage by a 
cutter formed to the correct shape, as indicated at E, 
Figure 45. Let us suppose that a number of blocks 
are to be made from blocks 2 inches long to have a 
form like that indicated. In order to produce a num¬ 
ber of pieces of this kind it is only necessary to make 
up a cutter of the required form and to mill a num¬ 
ber of long strips on the milling machine. The strips 
can afterward be sawed up into short pieces each of 
which is 2 inches long. 

All milling cutters are “relieved’’ at the back of 
the tooth, in order to provide chip clearance for chips 
removed from the work by the cutting action and 
also to prevent the back of the tooth from rubbing 
on the work during the operation. Formed cutters 


MILLING AND PLANING 


83 


like the one shown at D, however, are given a differ¬ 
ent kind of relief, called an eccentric relief, which 
permits the cutter to be re-ground a number of times 
after it becomes dull without changing the shape of 
the piece milled. 

Miscellaneous Cutters. —It is obviously impossible 
to describe and illustrate every type of cutter without 
entering into a lengthy discussion of the subject of 
milling. Such a discussion is unnecessary here. The 
descriptions show that varieties to meet every con¬ 
dition can be made. Figure 46 shows a group of 
common cutters used for various purposes in the 
average factory. The cutter, A, is generally termed 
a “hob.” It is used for milling the teeth in a worm 
gear, the work being held on an arbor either on a 
milling machine or a gear hobber. In making such a 
cutter the shape first produced is very similar to a 
worm gear and the teeth are formed by cutting longi¬ 
tudinal grooves. Each of the teeth is then relieved, 
and the cutter is hardened and ground ready for 
work. A hob cutter, when used for a worm gear, 
must always be made up specially for any piece of 
work. Gear teeth of the spur variety, however, are 
cut with so-called generating hobs on regular gear- 
hobbing machines, which can be bought in stock 
sizes according to the pitch of the teeth and the kind 
of machine on which they are to be used. Each hob, 
however, is made for a specified pitch of tooth and 
can be used only for this pitch. 

In this connection an amusing incident occurred 
some years ago in a New England factory where 
there were a number of apprentices. One of the ap- 


84 


TOOLS AND PATTERNS 



FIG. 46 . (a) worm hob cutter, (b) side or straddle mill¬ 

ing CUTTER. (c) PLAIN MILLING CUTTER. (d) IN- 
SERTED-BLADE CUTTER. (e) INTERLOCKING 
MILLER CUTTER 

































MILLING AND PLANING 


85 


prentices was sent to the tool room by the tool maker 
for whom the hoy was working, who told him to get 
“the hoh used for the big gear on Machine No. 1272.’’ 
On the way to the tool room the boy forgot the num¬ 
ber of the machine, but nevertheless he asked the 
tool crib man to “give me a hob for a big gear.” 
“What machine is it for?” the man asked him. “Oh, 

I don’t remember the number of the machine, but you 
better give me the biggest one you’ve got ’cause it s 
a big gear.” Needless to add, he was told to beat 
it, and get the machine number.” 

The cutter, B, Figure 46, is a side-milling cutter 
used as a single cutter for side milling or for facing 
a piece of work. It is also frequently used in gangs 
of two or more spaced the required distance apart 
for “straddle milling.” For example, if a boss on 
the end of a lever needs to be faced on each side, 
two side-milling cutters would be properly spaced on 
an arbor in the milling machine so that the distance 
between the cutters would be the same as the width 
of the finished boss on the lever. Given the proper 
kind of fixture for holding the work, then, a great 
number of pieces could be machined one after the 
other with perfect uniformity until the cutters were 
so worn as to require readjustment. 

For heavy work of large diameter inserted-tooth 
facing-mills, D, Figure 46, are used both singly and 
in groups for the same purpose as the side cutter, B. 
Cutters of this kind are largely used for making 
heavy facing cuts on both cast iron and steel. They 
will also produce good results on aluminum or brass. 
On vertical milling machines and multiple spindle 


86 TOOLS AND PATTERNS 

machines this type of cutter is extensively used for 
general manufacturing. 

The plain milling cutter, C, is intended only for 
surfacing or milling broad flat surfaces. It is most 
frequently used for milling steel. Frequently this 
cutter is set up with two or more side-milling cutters 
to mill a flat surface and at the same time to straddle 
mill both sides. It will be noted that the teeth on the 
cutter are milled spirally in such a way that as the 
cutter revolves each tooth engages the work progress¬ 
ively with a shearing cut, thereby producing a very 
fine finish with little likelihood of chatter. It is well 
to state at this point that no matter what style of 
cutter may be used on any piece of work some chat¬ 
ter may result. Loose gibbing (loose attaching) on 
the table of the machine is a frequent cause, the 
remedy for which is apparent. Another cause is a 
poorly designed fixture for holding the work or an 
inefficient method of clamping the work in the fixture. 
Still another is the use of an incorrect speed or im- 
pi oper feed, or a combination of both, which will be 
discussed in a later chapter. 

Interlocking Cutters.—In many processes of manu¬ 
facturing occasions arise when it is necessary to mill 
a slot in the work to a specified size within close 
limits of accuracy. The ordinary type of side¬ 
milling cutter, B, Figure 46, if used for this work 
soon becomes so worn on the sides that, after grind¬ 
ing a few times, it is a trifle under size and does not 
cut the slot to the required dimensions. When such 
a condition as this arises, therefore, an interlocking 
cutter, E, Figure 46, should be used. This illustra- 


MILLING AND PLANING 


87 


tion shows that the cutter is really a double cutter, 
made up of two parts which fit into each other in 
such a manner that every other tooth laps over an 
imaginary center line drawn around the circumfer¬ 
ence of the cutter. By this arrangement the teeth 
of the cutter may he adjusted by placing a disc of 
thin paper between them when they become slightly 
worn, the paper disc being made thick enough to 
compensate for the wear caused by hard usage and 
frequent regrinding. Such a cutter can be kept up to 
accurate size, and will always produce a piece of 
work within the required limits. 

Planing Tools. —Surfaces requiring the greatest ac¬ 
curacy are often planed instead of being milled. This 
is particularly the case with heavy castings such as 
machine beds and heavy fixtures, or parts of ma¬ 
chines which are a sliding fit on each other such as 
the cross slide on a turret lathe, the carriage on an 
engine lathe, the table of a milling machine and other 
work of similar character. In large manufacturing 
work—the building of locomotives, steam engines, 
compressors, or printing presses—the planer is a valu¬ 
able adjunct; but for smaller manufacturing the mill¬ 
ing machine is much more largely used, not only on 
account of its superiority in the matter of rapid pro¬ 
duction but also because it does not require so experi¬ 
enced an operator as the planer. 

The tools used in planing are generally single 
forged tools of a nature similar to those used on the 
engine lathe. There is a little difference in the shapes 
of "the tools, however, since in the one case the work 
is revolving, while in the other the work is moving 


88 


TOOLS AND PATTERNS 


along in a horizontal direction. Except for the fact 
that planer tools are somewhat heavier than lathe 
tools, there is so little difference in them that it is 
rather unnecessary to go into an extended description 
of them. It should also be remembered that the 
planer is not used to any great extent in interchange¬ 
able manufacture, so that the tools are not so highly 
specialized hut, more frequently, are ground in a 
slightly different way to suit the particular case. 


CHAPTER VI 


BROACHING 

The Purposes of Broaching. —The process of broach¬ 
ing holes, either round or rectangular, is by no means 
new, but modern methods differ from those in use a 
few years ago. In present-day practice the broach 
is pulled through the hole as a rule, while the former 
method favored a pushing action in forcing the tool 
through. Strictly speaking the broaching of a hole 
is a shaving operation produced by a number of cut¬ 
ting edges on a tool of suitable form. The teeth on 
the broaching tool are so arranged that progressively 
they come in contact with the work as the tool is 
forced through. Each tooth is set out beyond the 
preceding one a few thousandths of an inch, the 
amount being dependent upon the length of the 
broach, the kind of material which is being cut, and 
the amount of stock which is to be removed. 

The design of broaches therefore must take into 
consideration the points mentioned and also the mat¬ 
ter of upkeep—re-grinding and replacement when 
worn. For example, it would not be economical to 
design and make up a broach which was to be used 
only for a couple of hundred pieces in as painstaking 
a manner as though the work consisted of several 
thousand pieces. It would be the part of wisdom to 


90 


TOOLS AND PATTERNS 


make up the tool as cheaply as possible consistent 
with good workmanship; but if several thousand 
pieces were to be broached refinements in design 
could be made so that replacements could be made as 
easy as possible. 

Preliminary Treatment. —The preliminary require¬ 
ments in broaching a hole are that the work shall have 
been previously drilled or bored, or that an opening of 
some sort in the piece is large enough to permit the 
entry of the small end of the broaching tool. It is 
also necessary to ensure that the work can be prop¬ 
erly held and so located that the broaching operation 
will be done in the correct location on or in the work. 
Sometimes a previously drilled or reamed hole can 
be used for locating the work precisely by slipping 
it onto a stud on the face plate of the machine. In 
some cases the broach itself acts as the locating 
medium. 

In order that the process of broaching may be 
more readily understood by the reader, let us assume 
that a gear blank has been drilled, bored and reamed, 
and that it is desired to cut a keyway through it, as 
in X, Figure 47. In this case the face plate of the 
broaching machine is provided with a “pull-bush¬ 
ing,” as it is called, in which a slot is cut to allow 
the broach, A, to pass through it. This pull-bushing 
then acts as a guide for the broach and at the same 
times locates the work properly for the operation. 
This broach, A, is called a “keyway” broach and 
may be purchased cheaply in standard sizes from the 
makers of broaching machines, or it may be made up 
in the tool room of any factory at comparatively 


BROACHING 


91 



FIG. 47 . SEVERAL VARIETIES OF BROACHING TOOLS 


small expense. One end of the tool is slotted, so that 
a pin can he used to couple it to the feed-screw mech¬ 
anism of the machine. The teeth on the broach, start¬ 
ing at the end where the slot is, are graded in such 
manner that the first tooth cuts a very shallow 
groove in the work, the next tooth increases the 
depth slightly, and the remainder of the teeth act in 
like manner progressively. The last four or five teeth 
in the broach cut the full depth of the slot, for the 
purpose of assuring the accuracy of the work in the 
event that some of the teeth become worn. 

Broaching a Square Hole.— As a broaching cut of 
any kind requires a powerful machine, it is evident 
that the wear on the broach is very severe. There- 














































92 


TOOLS AND PATTERNS 


for to relieve the machine as far as possible and also 
to provide for long life in the broach itself, it is 
customary in broaching a square hole to drill the 
work out previously to a diameter slightly larger 
than the distance across the flat surfaces of the 
square, as shown at Y, Figure 47. The broach, B, is 
the type used for a square hole. The slotted end is 
cylindrical and a trifle smaller in diameter than the 
previously reamed hole so as to act as a pilot in 
guiding the square portion of the broach into the 
hole. Broaches of this variety are made of a single 
piece of carbon steel, machined to the shape indi¬ 
cated, and carefully hardened and ground before 
being used. The teeth also cut progressively as in 
the instance previously mentioned, the amount cut 
by each tooth being slightly in excess of that taken 
by the tooth just ahead of it. 

In broaching steel, the teeth of the broach are 
usually well lubricated at the moment before they 
enter the hole, thus reducing the friction of the cut 
and carrying away the heat generated. The proper 
lubricant is determined by the material which is to 
be cut. The various important matters connected 
with the subject of lubrication, however, will be 
found in Chapter XIX. 

Broaching a Round Hole. —Formerly, the proper 
method of obtaining a cylindrical hole to a given 
dimension was by the reaming process. The ordinary 
procedure was to bore the hole with roughing and 
finishing boring tools, leaving a few thousandths of 
an inch of metal to be removed by the reamer. 
Recent developments, however, have shown that a 


BROACHING 


93 


round broach can be used to better advantage. The 
finish in the hole produced by a broach is superior 
to that made by a reamer, and the required size can 
be easily obtained. In the matter of upkeep, also, the 
broach is superior to the reamer, although its first 
cost may be somewhat higher. As to accuracy, the 
modern broaching machine can be fitted with fixtures 
for holding the work and locating it so exactly that 
center distances can be precisely maintained. As a 
matter of fact the broaching process may be con¬ 
sidered as a precision operation. 

When it is desired to broach one hole in a piece 
in a definite relation to another, it is only neces¬ 
sary to locate a stud on the face plate of the machine 
at the proper distance from the center hole and pro¬ 
vide a broach of suitable form. It will be under¬ 
stood that when the hole is a single one and not 
located accurately with relation to some other one 
in the work the broaching machine centers the broach 
in the work by the previously reamed or bored hole. 
In such a case no special fixture is needed. 

In the case illustrated in Figure 48, a very accurate 
location is necessary between the two centers, A and 
B, in the work, C, an automobile connecting rod. 
Prior to the operation shown, the hole, A, has been 
drilled and broached to the proper size, no fixture 
being used in the operation and the hole itself acting 
as a locating point. For the operation shown the 
work is located on a stud on the face plate by the 
hole, A, which is located the correct distance from 
the other hole, B, the latter being the center line of 
the broach itself. For work of this nature the broach- 


94 


TOOLS AND PATTERNS 



FIG. 48. METHOD OF BROACHING A CONNECTING ROD 


ing machine must be furnished with supplementary 
equipment in the nature of a support table and slide 
as indicated in the illustration. The slide, D, sup¬ 
ports the end of the broach and centers it correctly 
as it is pulled through the work. Most excellent 
work can be done with such equipment. The broach, 
C, Figure 47, is used for round holes, and differs from 
B only in shape. Naturally the teeth are formed by 
a series of progressive rings instead of squares. 

Four-way Keyway Broaches. —In automobile and 
machine tool work it is sometimes necessary to cut 
four keyways in a piece of work which may be either 
a sliding fit or a close fit on a shaft, four keys being 
set into it for the purpose of providing an efficient 
method of driving. When such a broaching job is 
to be done the broach is made up in a somewhat dif¬ 
ferent way than those previously described. In Fig¬ 
ure 47, D, the cutting blades, F, are made up separ¬ 
ately and are fitted to the body of the broach, E, by 
some approved method, such as the screws indicated 




















BROACHING 


95 



FIG. 49 . EXAMPLES OF IRREGULAR HOLES THAT CAN BE 
BROACHED 


in the drawing. Other methods of fastening are also 
used, and, generally speaking, a method should be 
adopted which permits adjustment and holds the 
blades firmly. 

Broaches For Irregular Holes.— Irregular forms, 
such as internal gears of some kinds, ratchet teeth, 
and many other varieties of holes, can be broached 
to advantage providing that the production is large 
enough to warrant the necessary expense of procuring 
the broaches. A few shapes which can profitably be 
broached are indicated in Figure 49. The form, A, 
is an internal cam, %-inch thick, made of steel. Sev- 




96 TOOLS AND PATTERNS 

eral of these pieces are generally broached at one 
time without the use of a fixture, the broach being 
formed to the required shape. The form, B, is out 
of the ordinary and serves to show the variety of 
work which can be done on a broaching machine. 
The four rectangular holes are made concentric with 
the center hole, the material being steel. An internal 
spur gear is shown at C, and a sprocket with an in¬ 
ternal ratchet is indicated at D. Both of these 
broaches are of the solid variety, formed to the cor¬ 
rect shape and the teeth cut in the same manner as 
those previously described. 


CHAPTER VII 


SURFACE AND CYLINDRICAL GRINDING 

Grinding Material. —Many persons take an errone¬ 
ous view of the process of grinding and consider that 
it is adapted only to the truing up of parts which 
have been hardened and which, therefore, cannot he 
cut by the ordinary type of tool. As a matter of fact 
the up-to-date factory employs grinding for many 
parts which have not been hardened at all. When 
parts have been hardened they are likely to be more 
or less distorted and out of true, and these distorted 
parts can be corrected by grinding with a wheel com¬ 
posed of emery, carborundum, alundum, or other 
abrasive. 

Many of the compositions used for making grind¬ 
ing wheels are produced by artificial means, but the 
chief natural abrasives are emery and corundum, the 
latter being used to a greater extent than emery. The 
abrasives produced artificially are composed princi¬ 
pally from carbide of silicon and bauxite fused at a 
high temperature in the electric furnace. The vari¬ 
ous trade names of the artificial abrasives and their 
composition and uses are as follows: 

Adamite is used in wheels for grinding materials 
such as steel either soft or in a hardened state. It 
is an artificial abrasive made in Austria, and is com- 
97 


98 


TOOLS AND PATTERNS 


posed of aluminum oxide with certain other materials 
fused together in an electric furnace at a high tem¬ 
perature. 

Aloxite is used in wheels for grinding the same 
class of materials as that mentioned above. It is a 
product of the Carborundum Co., and is made by a 
special process from aluminum oxide crystals pro¬ 
duced by fusing mineral bauxite in an electric fur¬ 
nace. 

Boro-carbone is a trade name for another product 
of bauxite, as manufactured by the Abrasive Material 
Co. This abrasive is used for grinding materials 
which possess high tensile strength. 

Carbide of Silicon is used for grinding brass, cast 
iron, and other materials which possess low tensile 
strength. It is a composition of coke and sand fused 
in the electric furnace. This material also is a prod¬ 
uct of the Abrasive Material Co. 

Carbolon is used for materials having a low tensile 
strength. It is made by the Vitrified Wheel Co., from 
coke and sand fused in the electric furnace. 

Carborundum is a very well known abrasive which 
is a chemical combination of carbon and silicon fused 
at a temperature of 7000 degrees Fahrenheit. 

Crystolon is an artificial abrasive made by the Nor¬ 
ton Co. It is particularly suited to the grinding of 
cast iron, brass, and other materials of low tensile 
strength. The chief ingredients of this abrasive are 
carbon and silicon. 

Corundum is a mineral derived from native alumina 
and is the purest of all the natural abrasives. It is 
also produced by artificial means in an electric fur- 


GRINDING 


99 


nace and, next to the diamond, it is the hardest of all 
known materials. In reality it is nothing more than 
crystallized aluminum oxide, whether obtained by 
either natural or artificial means. The artificial 
product can be obtained in many grades suited to 
many varieties of work. 

Emery is used for obtaining a fine finish on bearing 
surfaces, ball races, and the like; but as an abrasive 
in manufacturing grinding processes emery has been 
largely superseded by some of the other materials 
mentioned in the foregoing list. While it is unex¬ 
celled for certain kinds of work, it does not possess 
the hardness nor does it have the free cutting quali¬ 
ties of some of the other abrasives. 

Grinding-Wheel Shapes.—Grinding wheels are made 
in a variety of sizes and in shapes of every kind for 
cylindrical work, shouldered work, forming, internal 
work, surfacing, and so on. Some of the more com¬ 
mon forms are shown in Figure 50, although these 
are but a very few of the many kinds and forms in 
use. In selecting a wheel shape for any piece of 
work, it is obvious that several things must be con¬ 
sidered—the kind of machine to be used on the work, 
for instance, or the form to be ground, or the method 
of presenting the wheel to the work itself. So many 
factors affect the shape of the wheel to be used, in 
fact, that it is out of the question to illustrate and 
describe the various kinds in a work of this kind; 
moreover such a description would be of no mateiial 
value to an executive for it would entail so great an 
amount of descriptive matter as to be confusing 
rather than enlightening. For the specific cases of 


100 


TOOLS AND PATTERNS 



FIG. 50. VARIOUS SHAPES OF GRINDING WHEELS 


grinding illustrated in this book the style of wheel 
shown in any particular case may be considered as 
the ordinary shape used for the work. 

Surface Grinding Methods.—When a plane surface 
which has been hardened or which, unhardened, needs 
careful finishing, it is frequently desirable to grind 
the surface to the required finish. Some machines 
which are used for surface grinding are adapted 
principally to light work requiring a high degree of 
accuracy, such as die blocks and other tool room 
work, while others are intended for general manu¬ 
facturing. When work is to be ground on a surface 
grinder it is of the highest importance that it should 
be held in such a way that there can be no “spring” 
or distortion arising from an improper method of 
clamping. Magnetic chucks—that is, magnetized 









































GRINDING 


101 


plates—are largely used for holding work which is 
to be finished in this way, although there are cases 
which require some more positive clamping action. 
The description of fixtures for holding work during 
grinding operations is dealt with in Chapter XVI. 

Several methods can he employed when a piece of 
work is to be finished accurately to a plane surface, 
and the one selected depends only upon the accuracy 
required in the finished product. Thus for a moder¬ 
ately good commercial job, two milling cuts—one 
roughing and the other finishing—may he taken with 
satisfactory results; this method is suitable for com¬ 
paratively narrow surfaces, such as the flanges on a 
transmission case in automobile construction or other 
work of similar character. For the surfacing of a 
machine bed or the finishing of the plane portions 
of locomotive cylinders, the planing operation will he 
most suitable. But for accurate die work and for 
gauges and the like a surface grinding operation or 
even a lapping operation* may be necessitated. 
Also for many operations in general manufacture 
where surfaces require a high finish within very close 
limits, the surface grinding operation offers many 
inducements; for example, in the finishing of rifle 
hammers over a hundred pieces may be laid on a 
magnetic chuck and ground both accurately and 
quickly. 


* Lanoing is not usually a manufacturing process. Primarily 
it consists of rubbing two surfaces—cylindrical or plane together 
with an abrasive such as flour emery between the surfaces. Fine 
gages are lapped to produce absolutely accurate work. Lapping is a 
Snd operation and does not enter into the ordinary processes of 


manufacture. 


102 


TOOLS AND PATTERNS 




















































GRINDING 


103 


Referring to Figure 51 the upper illustration shows 
a piece of work, A, with a flat surface, such as a die, 
which is to be ground after it has been hardened. In 
such work a machine having a horizontal spindle is 
employed and a thin wheel is used. The work table 
reciprocates—moves back and forth—under the wheel 
and feeds transversely at the end of each stroke, so 
that the entire surface of the work is ground in a 
series of parallel cuts. The wheel spindle is so ar¬ 
ranged that it can be raised or lowered by a screw 
with micrometer adjustment, thus very accurate work 
is easily produced. Strictly speaking, a piece of work 
which is to be ground on this type of machine is 
more often found in the tool room than in general 
manufacturing, although the machine can be adapted 
to certain classes of high-grade manufacture. 

The work, B, gives an excellent example of grind¬ 
ing, the work involved being a cast iron ring which 
is to be accurately ground to a uniform thickness. 
In this case also a magnetic chuck is used to hold 
the work and a rotary table is employed. The spindle 
of the machine moves back and forth over the surface 
of the ring as indicated by the arrows in the illus¬ 
tration. The wheel used for this class of work is 
similar to that used in the previous example, and also 
this kind of grinding is used principally with work 
which has been previously finished to within a few 
thousandths of an inch of its required size. It is well 
suited to the finishing of packiing rings for steam 
engines, automobiles, compressors, and the like. 

For heavier manufacturing and more severe cuts 
on larger work, a machine of a different type is more 


104 


TOOLS AND PATTERNS 


frequently used, which has the spindle nearly vertical 
but with a very slight inclination to provide for clear¬ 
ance behind the cutting edge of the wheel. In an 
example of this kind, it will be noted that the wheel 
is shaped like a cup, usually called a cup wheel. The 
work, C, may be held on the table of the machine by 
means of a magnetic chuck or by clamps, depending 
upon its shape and the material from which it is 
made. For long work a machine having a reciprocat¬ 
ing table is often used, and it is often possible to 
have several pieces on the table at the same time. 
For this kind of grinding the wheel should be of suffi¬ 
cient size to cover the entire width of the work. The 
speeds and feeds at which different kinds of grinding 
are done will be considered in Chapter XX. 

Cylindrical Grinding. —In cylindrical grinding the 
work is frequently held on centers when it is of such 
a nature that one end can be dogged* for the purpose 
of driving. But it is not always that centers can be 
used on cylindrical work, and the chuck is frequently 
used for the purpose. In such cases it is of extreme 
importance to arrange the holding device in such a 
way that it will not distort the work. As in surface 
grinding the pieces to be ground may have been 
hardened previously or they may be soft, but in 
either event the operation of grinding and the method 
of presenting the work to the wheel are identical. 

The shape of the wheel used for cylindrical grind- 


* A dog is a simple sort of clamp used for cylindrical work to 
act as a means of driving. Several types of dogs can be found in 
every machine shop. Dogs are usually provided with a setscrew to 
hold the work firmly and a tail which enters a slot in the faceplate 
and acts as a driver. 



GRINDING 


105 


ing is usually like that shown in Figure 52 at A, al¬ 
though variations of the shape occur to suit different 
conditions. Let us suppose, for example, that a piece 
of work of cylindrical shape is to he ground, and that 
at the end of the ground surface there is a ^fillet 
which is also to be ground. In such a case the wheel 
which would come in contact with the fillet would be 



FIG. 52. CYLINDRICAL AND INTERNAL GRINDING METHODS 





















































106 


TOOLS AND PATTEBNS 


so shaped that it would finish the form at the end of 
the stroke. 

If there are several diameters to be ground and a 
great number of pieces are to be finished, it is com¬ 
mon to make a separate operation for each diameter. 
The reason for this is that the diameter stops and 
indicating dial on the machine can be set for repeti¬ 
tion work to better advantage if a single diameter is 
handled at one time. 

When cylindrical work is to be ground up to a 
shoulder and leave a sharp corner, it is customary 
to provide a nick close to the shoulder so that the 
wheel can “run out” at this point, as shown at B, 
Figure 52. 

External Taper Work.—When a piece of taper 
work is to be ground the process is practically the 
same as for straight cylindrical work, except that 
the machine carriage is swung to the proper angle to 
generate the correct taper. The form of the wheel 
is the same as that shown at Figure 52, and the 
method of dogging and centering the work is also 
the same. 

External Form Grinding.—For some work where 
a form of a prescribed shape is to be ground on the 
outside of a cylindrical piece, the wheel is fed di¬ 
rectly into the work until the proper depth is reached, 
as indicated in Figure 52, C. The process of form 
grinding has lately been developed to a great ex¬ 
tent in the grinding of such forms as shrapnel, rifle 
barrels, and other forms which have to do with muni¬ 
tion-making and small arms. In grinding a shrapnel 
shell, for example, the wheel for one operation is 


GRINDING 


107 


formed to take the curve on the end of the shell, 
while in the operation of grinding the straight por¬ 
tion of the body a wide wheel is used for one portion 
and a narrow wheel on another part. In grinding 
rifles, the barrel is usually ground at an approxi¬ 
mately central location on the length of the barrel 
to provide a smooth surface for the steady-rest; the 
tapers are then ground with a formed wheel accord¬ 
ing to their variety and shape, and the cylindrical 
surfaces are handled in the usual manner. If there 
are any tapered surfaces on the barrel, these may be 
either ground with a formed wheel or the grinding- 
wheel carriage can be set over to the required angle 
for generating the taper. 

Internal Grinding.—The process of internal grind¬ 
ing is applicable to either straight or tapered sur¬ 
faces, but the work must be performed with an in¬ 
ternal attachment, such as that shown at E, Figure 
52. The wheel, D, in this case is of much smaller 
size than the type of wheel used for external grind¬ 
ing, although it is practically the same shape. The 
process of internal grinding is particularly useful in 
the making of bearing bushings and other work of 
similar character. The work may be either straight 
or tapered; both kinds can be handled with equal 
facility providing that the angle of the taper is not 
too great for the carriage to accommodate it. 

In the example shown, the work has been previ¬ 
ously machined and a sufficient allowance has been 
made for grinding before the hardening operation. 
The work is held in a special form of chuck as indi¬ 
cated, and the wheel, D, passes back and forth in the 


108 


TOOLS AND PATTERNS 


work until the desired diameter has been ground. 
Suitable adjustments for diameter can easily be made 
on the machine, and it is entirely possible to keep 
manufacturing work within a limit of 0.00025 inches 
on the diameter. Many varieties of chucks are used 
for this class of work and some of these are of par¬ 
ticular interest in the provision made for locating, 
holding, and driving the work without distortion. 
These will be dealt with more specifically in Chapter 
XVI. 

Cylinder Grinding. —In automobile manufacture, 
and also in the manufacture of compressors and other 
work of this kind, the process of grinding the inside 
of the cylinders is extremely important. For this 
purpose a cylinder grinding machine has been de¬ 
veloped by the Heald Machine Co., which operates 
on a different principle from those used in ordinary 
internal cylindrical grinding. It may be noticed that 
in the preceding example of internal grinding, the 
work revolves around its own center and different 
diameters are ground by re-setting the wheel spindle. 
In the Heald cylinder grinding machine, however, 
the work is so arranged that it does not revolve but 
the wheel spindle is given a double movement—that 
is, a rapid turning movement of the wheel on its own 
center and an eccentric rotary motion of the spindle 
itself. The spindle is so arranged that it can be set 
sufficiently eccentric to the center, within the capacity 
of the machine, to describe a circle equal to the 
diameter to be ground. Pieces such as an automobile 
cylinder, especially cast “en bloc,” can be arranged 
on the carriage of the machine so that one hole can 


GRINDING 


109 


bo ground to size and the carriage set over the cor¬ 
rect center distance to grind the other cylinders. 
Other data in regard to the grinding of automobile 
cylinders will be found in Chapter XVI, Grinding- 
Fixtures. 


CHAPTER VIII 


SHOP EQUIPMENT 

Standard Equipment. —Any factory which is in¬ 
tended to produce work at a minimum expense must 
be properly equipped in its various branches. The 
tool crib must be well supplied with all standard 
sizes of drills, counterbores, reamers, boring tools, 
taps and dies, and all the other implements which 
may be assumed to be a part of the tool crib equip¬ 
ment. Such tools as milling fixtures, drill jigs, bor¬ 
ing fixtures, and the like, also form a part of the 
equipment, but these are so varied that they can¬ 
not be considered as standard equipment. Cutting 
tools which lose their cutting properties when dull 
must be taken care of by resharpening, and the tool 
crib should be provided with the necessary grinding 
machines for drills, reamers, cutters, and forged tools. 

In addition to the above, there are certain other 
tools which may be considered more nearly a part 
of the actual shop equipment. These tools are in 
the nature of surface plates, straight-edges, parallels, 
V-blocks, C-clamps, vises, etc. Also, certain other 
instruments, such as surface gauges, micrometers of 
large size, calipers, special gauges such as gauges for 
taper sockets, thread gauges, and other instruments 
for determining standard shapes, tapers, and so forth, 
should be provided. 


no 


SHOP EQUIPMENT 


111 


The toolmaker is ordinarily considered to have an 
equipment of tools of his own, such as small size 
micrometers, calipers, surface gauges, squares, and 
protractors; and although some of these tools may be 
included in the shop equipment, they are more in the 
nature of special instruments sued for checking pur¬ 
poses and for testing. Omitting tools of this kind 
from the discussion, then, we have as a part of the 
shop equipment the tools that are in daily use and 
kept in the tool crib strictly for the use of the work¬ 
men in producing work to the best advantage. We 
have also the tools which are fastened in place, such 
as vises which are bolted to benches all around the 
shop. 

Surface Plates. —Referring to Figure 53, the upper 
illustration, A, shows a form of surface plate which 
should be considered as a part of the standard equip¬ 
ment of any factory. Plates of this kind are made of 



FIG. 53. SURFACE PLATES AND STRAIGHT EDGES 






















112 TOOLS AND PATTERNS 

cast iron, well ribbed so that they will not easily 
get out of alignment. The surface of the plate, B, 
has been planed and scraped to a perfect plane, so 
that it can be used for testing other surfaces or for 
the fitting of parts. Several of these plates of dif¬ 
ferent sizes can be found in any toolroom set up here 
and there on the workmen’s benches. When a piece 
of work is to be tested or laid out with a scriber or 
surface gauge, surface plates are essential. Also in 
fitting another plate or piece of work which must be 
a perfect plane, the surface plate, rubbed with a little 
Prussian blue, can be brought in contact with it in 
such a way that the “high spots” will show a blue 
mark from the contact. These blue marks can then 
be scraped off with a hand scraper, as described in 
Chapter I. A plate of this kind is more often used 
in the toolroom than in any other department, al¬ 
though every department in the shop should have one 
or more for testing purposes, and for gauging and 
laying out work. 

Straight-edges and Parallels.—It is often necessary 
to determine whether a surface is straight or not, and 
this determination is also a valuable adjunct in set¬ 
ting up. The ordinary straight-edge, C, Figure 53, is 
generally kept in the toolroom and taken out by a 
workman when he needs it. It is usually made of 
cast iron, with a face, D, which has been scraped to a 
perfect plane. In order to lighten the tool and make 
it more convenient for a workman to handle, a num¬ 
ber of holes are pierced through it as indicated in 
the illustration. Straight-edges are made in lengths 
from 18 inches to 15 feet, according to the work for 


SHOP EQUIPMENT 


113 


which they are intended; special sizes can he obtained 
to order. These straight-edges are not commonly 
used for the smaller varieties of work nor for the 
very finest class of work. 

Another type of straight-edge, E, Figure 53, usually 
called a toolmaker’s knife-edge straight-edge, may oc¬ 
casionally be found in tool cribs, although it is more 
often a part of the toolmaker’s personal tool kit. 
These straight-edges are used for work that requires 
extreme accuracy. Hence, they are made from the 
best quality of steel treated with the utmost care to 
insure that they will be straight and true. In the 
finest kind of toolmaking work these straight-edges 
are extremely valuable, and the workmen who use 
them take the greatest care to see that their accuracy 
is not impaired through springing or injured by be¬ 
ing dropped. 

Parallels, F, Figure 53, are found in great variety 
and in numerous sizes in the tool crib. They are use¬ 
ful for setting up work of more or less irregular 
shape when the work has been previously machined 
on one side and can not possibly be clamped to the 
table of the machine for a succeeding operation. 
Parallels may be made of steel or of cast iron, de¬ 
pending on their size 5 the smaller parallels are usu¬ 
ally made of steel and the larger sizes of cast iron. 

Frequently a piece of work may be set up and 
clamped to a pair of parallels and machined when it 
might otherwise be very difficult to hold the piece 
without a special fixture of some sort. In fact, the 
uses of parallels in any factory are so many and their 
application is so varied that it is difficult to mention 


114 


TOOLS AND PATTERNS 


all of their uses. It may be said, however, that no 
factory can be called complete without having as a 
part of its shop equipment a great number of paral¬ 
lels of different sizes and sections. 

Hand Vises. —One of the most important things in 
machining any piece of work is to hold it firmly. As 
the shapes which are to be held are of so many 
varieties, shapes, and sizes, it is obvious that there 
must be numerous types of holding devices which 
can be applied to the work. The importance, there¬ 
fore, of the various clamps which are used for hold- 



FIG. 54. HAND VISES, C-CLAMPS, AND V-BLOCKS 

































SHOP EQUIPMENT 


115 


ing work, locating two pieces in definite relation to 
each other, and so on, in all kinds of operations, can¬ 
not he overestimated. 

A group of small tools which can he considered as 
a part of the standard equipment of any factory is 
shown in Figure 54. The hand vise, A, may he used 
for a variety of purposes by the toolmaker or other 
workman. It will he seen that the jaws of the vise 
are kept in a state of parallelism hy the equalizating 
cross, B. When the thumb-nut is operated, the jaws 
open or close according as the nut is loosened or 
tightened. For holding a small piece of work on 
which a filing operation is to he done, for, example, a 
hand vise of this kind is very useful; and for numer¬ 
ous other operations which require the holding of a 
piece of small work in a certain fixed position this 
tool is almost indispensable. As a general thing this 
tool is more frequently found in a toolmaker’s kit 
than in the tool crib. 

It is often necessary to hold two pieces of work 
together when some machining operation is to he 
performed on them—for example, when two pieces 
are to he drilled and reamed together. In such work 
the toolmaker’s clamp, C, Figure 54, is an important 
accessory to the tool crib. This clamp is really a 
type of hand vise in which the two jaws, C, C, are 
tapped to receive the thumb screws, D. The two 
jaws are operated hy means of the thumb screws, and 
can he tightened hy the fingers upon a piece of work. 
If additional pressure is needed, a pin hole m the 
end of the screw can he used as a holder for a small 
lever. Ordinarily this clamp is used for holding fin- 


116 


TOOLS AND PATTERNS 


ished pieces together, not those which are in a rough 
state. 

C-Clamps.— When rough work is to he held firmly, 
or when a piece of work is to be clamped down on a 
machine or clamped against a parallel, the C-clamp, 
shown at E, Figure 54, is generally used instead of 
the toolmaker’s clamp previously mentioned. This 
C-clamp is provided with an anvil, F, and a screw, 
G, by means of which the necessary pressure can be 
exerted. The body of the clamp is usually a drop 
forging which is capable of withstanding consider¬ 
able pressure. C-clamps should be found in the tool 
crib in great variety, both as to size and also in re¬ 
gard to the depth or throat opening which determines 
the sizes of work that may be held. For holding 
large work on the planer or milling machine and for 
a variety of other purposes in connection with manu¬ 
facturing, the C-clamp is used to a great extent and 
must certainly be included in the shop equipment. 

V-Blocks.— When a piece of round work is to be 
held so that it can be drilled or otherwise machined 
and no fixture has been designed for the work, one 
or more V-blocks, H and K, Figure 54, can be used 
to make up a temporary fixture. The particular type 
illustrated has a groove along the side to which a 
special form of clamp can be applied, as indicated at 
M. The arrangement shown in the illustration is 
used for holding a tube, N, to locate it properly for 
machining operations—drilling, milling, or cutting a 
key-slot. The bases of the V-blocks are parallel with 
a centerline of the V-shaped cut in the block, so that 
when the work is set up on the machine it will lie 


SHOP EQUIPMENT 117 

parallel to the surface on which the blocks are 
clamped. 

V-blocks are often used for straightening a piece 
of work. In this case the work is clamped by two of 
the blocks in such manner as to bring the bent por¬ 
tion between the blocks where it can be struck with 
a hammer or straightened under an arbor press. The 
application of the V-block principle to many forms of 
mechanical work will be further described in Chap¬ 
ters XVII and XVIII. 


. Fv 



6 '" 


FIG. 55. BENCH AND PIPE VISES 

Bench and Pipe Vises.— Any attempt to describe 
the shop equipment of the factory without mention¬ 
ing the bench vise would be very much like a dinner 
without dessert or a roast of beef without salt. The 
bench vise, A, Figure 55, is an ordinary type of 
machinist’s vise which is bolted to the workmen s 
bench at frequent intervals in every department. The 
type shown is equipped with a swivel jaw, B, by 
means of which a piece of tapered work can be firmly 










118 


TOOLS AND PATTERNS 


held without slipping. A pin, C, is provided to lo¬ 
cate this swivel jaw in a fixed position parallel to the 
movable jaw, D. A tapered piece of work, E, is 
shown clamped in position in the vise. It is evident 
that vises of this kind are an absolute necessity in 
any factory, no matter what the product or how large 
the factory. There are so many operations which need 
the assistance of a vise that it would be out of the ques¬ 
tion to attempt to describe all of its uses. 

When a bench vise is to be used for holding a piece 
of finished work or something which must not be 
marred, it is often provided with a set of soft jaws, 
F, usually made of babbitt metal or copper, but some¬ 
times made of sheet brass or tin. Babbitt metal jaws 
are very short lived and crush or break very easily, 
so that they become useless in a comparatively short 
time. Copper jaws or those made of heavy brass 
will last almost indefinitely if carefully used. The 
vises in many shops are provided with false soft jaws 
for general use, and babbit molds for making jaws 
of this kind are in common use. 

The pipe vise, G, Figure 55, is frequently found 
in shop equipments, although its principal use is in 
plumbing work and pipe fitting. It is a convenient 
accessory for shop use, however, although one vise in 
a department is usually considered sufficient. The 
type shown is provided with a set of V-shaped corru¬ 
gated jaws which grip cylindrical work and prevent 
it from turning while a thread is being cut. The 
upper jaw is operated by means of the screw and 
handle shown, and the latch, H, allows the entire 
upper part of the vise to be backed out of the way. 


CHAPTER IX 


MACHINE EQUIPMENT 

Necessity for Proper Tools. —A man may purchase 
a machine at considerable expense and may find, after 
it has been in use for a while, that he is not getting 
as much out of it as he expected to. This may be 
for one of several reasons: It may be that the oper¬ 
ator is inclined to loaf on the job; it may be that the 
cutting speeds and feeds are not correctly deter¬ 
mined; or it may be that the tool equipment is in¬ 
adequate. Disregarding for the time the first and 
second cause, it is certain that any machine to per¬ 
form its functions in a satisfactory manner must 
have a proper equipment of tools. 

When the work is of the interchangeable variety 
the matter of tool equipment needs most careful con¬ 
sideration. And even for the ordinary machine equip¬ 
ment certain tools are indispensable if the work is 
to be turned out in good style and with a minimum 
expenditure for labor. The equipment of the tool 
crib for standard machines in any factory, therefore, 
should be very complete, so that the workman will 
never be obliged to use a “ make-shift” method in 
preparing to do any piece of work. 

When boring out a drill jig for bushing holes, or 
something of this kind, the toolmaker, naturally, is 
119 


120 


TOOLS AND PATTERNS 


obliged to use a certain amount of ingenuity when 
lie “sets up” work on the machine. However, this 
display of ingenuity should not be considered in the 
line of a make-shift, because in such work each job 
is a special one and needs special care in the setting 
up. 

In this chapter I will consider only the type of 
tools which may be considered as a part of the 
standard equipment and those which should be kept 
in the tool crib as a part of such equipment. Tool 
equipment for various machines has been or will be 
taken up in this book, under their proper headings, 
but the types I will describe at this time, although 
they may be similar in some respects to the others, 
are decidedly ranked as standard equipment. 

Drill Chucks and Sockets. —Referring to Figure 56, 
the drill socket, A, is tapered on the outside to fit 
the spindle of the drill press, and the tang, B, acts 
as a driver. A “taper shank” drill is used in a 
socket of this kind, the tang of the drill being driven 
into the slot, C. These sockets form a part of the 
equipment of any tool crib. They are made up in 
various standard sizes for different kinds of tapers. 
These tapers are slightly different for various ma¬ 
chines, and are known as Morse taper, Brown & 
Sharpe, Jarno, etc. They are designated by number 
and name, and are all slightly different, both in sizes 
and also in the angle of the taper. For instance, 
if a drill press, having a No. 4 Morse taper hole in 
the spindle, is to use a comparatively small drill hav¬ 
ing a tapered shank of No. 2 Morse taper, a socket 
having a No. 4 taper outside and a No. 2 taper inside 


MACHINE EQUIPMENT 


121 



FIG. 56. DRILL CHUCKS, SOCKETS, AND TAPPING ATTACHMENTS 

would be selected. The No. 4 taper would fit the 
spindle of the machine and the inside of the socket 
would fit the shank of the drill to meet the condition 
required. 

An excellent socket for drill press use possessing 
many advantages is shown at D, Figure 56. This is 
known by the trade name, “magic chuck,” and is 
made by the Modern Tool Co. When a number of 
sizes of drills or other tools are to be used in succes¬ 
sion in manufacturing work, a socket of this kind is 
extremely valuable, for tools can be changed with 































122 


TOOLS AND PATTERNS 


great facility while the machine is running. The 
socket proper has a tang that fits the spindle of the 
drill press. On the outside of the socket a sliding 
sleeve, E, fits loosely and is prevented from dropping 
off by the small retainer, F, which rests in a groove 
cut around the chuck. The lower part of the sliding 
sleeve is bored out to the diameter of the two steel 
balls, G, lying normally in opposite drilled holes in 
the chuck. A special form of adapter for the drill, 
shown at H, has a tapered hole and a slot in the end 
for driving the tang of the drill. 

The action of the chuck when in use is as follows: 
The operator has the tool—drill or other tool—in its 
socket hut not in the chuck proper. In order to place 
it in position while the spindle is revolving, he grasps 
the sleeve, E, and lifts it with his left hand. This 
allows the balls, G, freedom to run out into the an¬ 
nular groove, K, so that the socket, H, can he pushed 
up into the hole. When the socket is pushed in to 
its full depth, the sliding sleeve, E, is released, and 
the halls, G, are forced hack thereby into their 
grooves on the outside of the socket where they act 
as drivers for the tool. If, for instance, several holes 
of different sizes are to be made on a one-spindle 
drill press and an equipment of Magic sockets is 
available, it is easily possible for an operator to 
substitute one tool for another and complete the hole 
in very short order without stopping the machine dur¬ 
ing the process of the work. Chucks of this kind are 
very useful as a part of the tool crib equipment. 

When small drills of the straight shank variety are 
to be held, another type of chuck is generally used. 


MACHINE EQUIPMENT 


123 


If they are of the smallest sizes, not requiring any 
great pressure to drive them, the type of chuck, L, 
is commonly employed. This chuck consists of a 
sleeve, M, threaded to the outside of the body of the 
tool and having an inside tapered portion which 
draws in on the three jaws, N. The jaws, in turn, 
grip the drill and center it at the same time. A 
chuck of this type is very common and should be 
found in every tool crib. 

Another type of chuck for drills which are a little 
heavier but have straight shanks is shown at 0, 
Figure 56. This chuck is made by the T. R. Almond 
Mfg. Co. The upper end fits a shank which is tapered 
to go into the drill press spindle. The three jaws, P, 
are controlled and moved in or out by the action of 
a bevel gear and threaded nut which is operated by 
a special wrench having a bevel pinion, Q, at the end. 
This chuck also is a very useful adjunct to the tool 

crib. . . 

Tapping Attachment for Drill Press. —When it is 
necessary to tap a hole or series of holes in a piece of 
work, and it is desired to perform the operation by 
means of a machine instead of by hand, a tapping 
attachment may be used for the work, applied to 
a drill press of the ordinary variety. The attachment, 
R, Figure 56, is made by the Braden Mfg. Co. This 
mechanism is so arranged that the spindle of the 
machine, when raised after the bottom of the hole 
has been reached, automatically reverses the direction 
of rotattion of the tap so that it backs out of the 

The operation of the mechanism is as follows. The 


124 


TOOLS AND PATTERNS 



spindle is raised and lowered with the right hand 
while the work is inserted with the left hand, so that 
the operation of the mechanism is almost continuous. 
The reversing gears are enclosed in a dustproof case, 
S, and need practically no attention. The gauging 
of the depth of the hole can he taken care of by 




















































































MACHINE EQUIPMENT 


125 


means of the adjustable stop, T. Several mechanisms 
of this kind are on the market, each of which has 
some feature to prevent the breaking of taps and 
also to make it unnecessary to reverse the spindle 
of the machine when in operation. 

Collets and Chucks. —Collets, sometimes known as 
draw-in chucks, are used on many types of machines. 
Probably the use to which they are most often ap¬ 
plied is in the holding of bar stock on the screw 
machine. They are also employed to a considerable 
extent on toolmakers ’ lathes, bench lathes, jewelers’ 
lathes, screw shavers, and the like. As a part of the 
shop equipment, however, their application is gener¬ 
ally to the toolmakers’ lathes and the screw machine. 

Several types of collets are used for these ma¬ 
chines, but for stock of small size the mechanism is 
most frequently like that shown at A, Figure 57. In 
this case the spindle is fitted with a nose piece, B, 
having a tapered hole in the forward end. A spring 
sleeve, C, is split in several places around the peri¬ 
phery in such a way that it will draw in or contract 
as it is pulled back into the tapered end of the 
nose piece. The method of pulling the collet back 
differs with the machine to which it is applied. In 
the case of a bench lathe or toolmaker’s lathe the 
mechanism is usually operated from the end of the 
spindle by means of a handwheel. When the device 
is applied to a hand screw machine, the draw-in 
mechanism is usually operated by means of a handle 
at the rear end of the spindle, but the action of the 
collet jaws in gripping the work is identical to that 
shown in the illustration. 


126 


TOOLS AND PATTERNS 


Several other types of collets are made for work 
of larger size, but these are more in the nature of 
chucks, and the jaws of the collet are loosely held 
and have no forward or backward movement. An 
example of a collet chuck of this kind is shown at D, 
Figure 57. In this case the nose piece is screwed to 
the end of the spindle and the jaws, E, are operated 
by a closer which slides forward on the tapered por¬ 
tion of the jaws when the sleeve indicated is pushed 
forward through the spindle. A particular advantage 
of this type of chuck is that there is no longitudinal 
movement to the jaws as they contract and expand. 
They can be used, therefore, for second operation 
work (that is, work which has previously been par¬ 
tially machined) with the assurance that the longi¬ 
tudinal position will come the same in every case. 

Step Chucks. —After a piece of cylindrical work 
has been machined in a previous operation and other 
work is to be done on it which will be true with 
that previously done, it is frequently held by the 
previously finished surface in either a collet, such as 
that noted in the preceding illustration, or by means 
of a step chuck such as that shown at F. Or an ex¬ 
panding arbor may be used when the work pre¬ 
viously done has consisted of boring and reaming a 
central hole in the piece. The step chuck principle, 
as shown at F, is extremely useful for finishing work 
of this character, G. The step chuck body, H, is 
operated by means of a mechanism in the same man¬ 
ner as the collet jaws previously mentioned. The 
chuck itself, however, in this case is made of soft 
material, so that it can be machined to the proper 


MACHINE EQUIPMENT 127 

size to hold the work while it is in the machine on 
which it is to he nsed. 

Taking the case shown as an example, the method 
of ‘‘stepping out” the chuck would he to place a 
piece of round stock of small diameter in the jaws 
and set up the closing mechanism. This work would 
he done on the machine. While in this condition, 
the chuck would he hored out to the diameter re¬ 
quired for holding the blank, G, after which the 
cylindrical piece would he taken out of the chuck 
which would then he ready for use. It will he seen 
that this mechanism is exactly similar in action to 
the collet shown at B, except that it is of larger 
diameter and, consequently, has a greater latitude. 

Two-Jawed Chucks.—Two-jawed chucks form a 
very useful part of the machine equipment, par¬ 
ticularly on small hand screw machines in the hold¬ 
ing of irregular work or pieces which cannot easily 
he held in a three-jawed scroll chuck. A chuck of 
this kind is shown at K, Figure 57, the small end 
being screwed directly to the end of the spindle. 
This chuck is commonly operated by means of a 
wrench, although various applications are made 
which provide a means of operating that is quicker 
than the wrench method. Sometimes compressed air 
operating on a plunger through the spindle is.used, 
and at other times a wedge or a rack-and-pinion is 
used, depending on the type of chuck and the method 
advocated by the manufacturer. 

In the type shown, the mechanism is controlled by 
means of a right- and left-hand screw, L, which is 
journaled at M in the body of the chuck in such 



128 


TOOLS AND PATTERNS 


manner that it has no crosswise movement. The 
jaws, 0, are tongued to fit a slot, P, running across 
the chuck, and the lower portion of the jaw is tapped 
out to receive the body of the right- and left-hand 
screw, L, previously mentioned. It will be seen that 
as the screw is operated, the jaws move in or out, 
according as the screw is turned to the right or left. 

Jaws of this kind are frequently provided with a 
dovetail into which sub-jaws, Q, can be inserted. 
This is done so that the same chuck can be used for 
a number of different pieces by simply making up a 
set of sub-jaws or inserted jaws of the desired form. 
In the instance shown in Figure 57, the work, R, 
which is being held, is of rectangular form, and the 
chuck is provided with two locating plates, S, to 
give the sidewise location while the jaws center the 
work in the opposite direction. 

When a two-jawed chuck is to be used for holding 
an irregular piece of work, the inserted jaws are gen¬ 
erally formed to the desired shape, after which they 
are hardened and set in place in the chuck. Jaws 
of this kind are very useful for small, irregular¬ 
shaped forgings or castings, and also, when applied 
to the larger variety of chucks, they can be used for 
heavier work of irregular form. For example, a 
lever having a long hub and a crooked arm, could be 
nicely held in a two-jawed chuck, with jaws shaped 
to fit the hub and so arranged that the lever arm 
would act as a driver. Such jaws may also be 
formed out to a radius to fit thin brass or bronze 
bushings which are to be bored and reamed; when 
formed in this way the bushings can be held so that 


MACHINE EQUIPMENT 


129 


there is very little distortion caused by excessive 
pressure in holding. 

Geared Scroll Chuck. —The ordinary chuck used for 
centering work on either a lathe or turret lathe is a 
three-jawed geared scroll chuck of a variety similar 
to that shown at A, Figure 58. Chucks of this kind 
have an excellent centering action, as the jaws are 
spaced at 120 degrees apart and all are moved radi¬ 
ally toward the center with an equal movement. 
This type of chuck can be mounted on a faceplate, 
as indicated at B, which is screwed to the end of the 
spindle of the machine, or the chuck can be so de¬ 
signed that it screws directly onto the end of the 
spindle. In either case the internal mechanism is the 
same, and is practically like that shown in the illus¬ 
tration. An annular ring, called the scroll, lies in a 
recess as shown at C. This recess runs entirely 
around the chuck and the scroll portion engages with 
the bottom of the three jaws, D, which are also 
tongued on their sides into radial slots in the body 
of the chuck. The face of the jaws is tongued to 
receive special jaws of different form, like that shown 
at E in the figure. These jaws are fastened by the 
two screws shown and can be replaced by others at 
any time with very litle trouble on the part of the 
operator. 

The chuck is provided with three pinions of the 
bevel type, F, which mesh with a bevel gear cut on 
the back of the scroll ring. When any one of these 
pinions is turned, by means of a socket wrench pro¬ 
vided with the chuck, the scroll, C, revolves in its 
bed and carries the chuck jaws radially inward or 


130 TOOLS AND PATTERNS 

outward, according as the pinion is operated to the 
right or left. 

Air-Operated Chucks.— The advantages of com¬ 
pressed air and the many uses to which it can be ap¬ 
plied in the factory are becoming more and more 
appreciated by the progressive manufacturer. Some 
years ago considerable interest was shown when a 
machine-tool builder of international reputation de¬ 
signed and built a very large fixture for use in his 
own plant, which had a series of clamps by means 
of which the work was held, the clamps being oper¬ 
ated by compressed air. An additional refinement 
was supplied by the designer in the introduction of a 
pressure valve so arranged that the amount of pres¬ 
sure applied to the clamp could be adjusted to provide 
the same amount of pressure under any condition. 
As the work was of large size and peculiar shape, 
there was danger of distortion if Tom, Dick or Harry 
were permitted to exercise his judgment in regard to 
clamping the work, but the application of compressed 
air and the pressure valve made the matter of hold¬ 
ing an absolutely safe proposition. 

In the past few years methods of chucking or hold¬ 
ing work on the turret lathe or screw machine have 
received a great amount of attention, and the prin¬ 
ciple of holding by means of compressed air has 
been made use of by several manufacturers. A very 
successful type of air chuck, made in a number of 
varieties by the Hannifton Mfg. Co., is shown at G, 
Figure 58. In the type shown the jaws are three in 
number, as shown at H, and on these jaws an adjust¬ 
able jaw, K, is mounted. By means of the screw, L, 


MACHINE EQUIPMENT 


131 



these adjustable jaws, K, can be set in or out in a 
radial direction toward the center of the chuck to 
provide for holding pieces of different diameter, oi 
they can be set eccentrically at different distances 
from the center to suit any particular case. On the 


























































132 


TOOLS AND PATTERNS 


adjustable jaws the work-holding jaw, M, is located 
by means of the tongue shown. 

The operation of the mechanism is as follows: The 
chuck is slotted in three places to receive the oper¬ 
ating levers, N, each of these levers being provided 
with an arm which enters a slot on the rear side of 
the jaws, H. A plunger, 0, runs back through the 
spindle and connects with the air cylinder at the rear 
of the spindle. The front end of the plunger is so 
grooved that it engages with the three lever arms as 
indicated at P. When it is desired to operate the 
chuck jaws, a conveniently located two-way valve is 
opened, allowing the air to enter the cylinder at the 
rear of the spindle and pull back upon the plunger, 
0, which in its turn, operates the lever arm, N, that 
moves the jaws inward in a radial direction to grip 
the work firmly. The amount of pressure used can 
be regulated by means of a pressure valve if desired, 
depending upon the work which is to be held, so that 
a delicate pressure or a powerful clamping action can 
be readily obtained. 

Air chucks of this kind are extremely useful for 
chucking work of various kinds on turret lathes and 
screw machines, and they can be obtained in a num¬ 
ber of sizes and shapes to suit the most fastidious 
customer. It is evident that special jaws can be 
adapted without difficulty to chucks of this kind, so 
that they can be made to handle a variety of work. 

Four-Jawed Independent Chuck.— In the course of 
general manufacturing, or for work in the tool-room, 
it happens occasionally that a piece of irregular 
shape needs to be held. In a case of this kind the 


MACHINE EQUIPMENT 


133 


three-jaw chuck cannot be used to advantage since 
it is adapted only for work which can be centered. 
For tool-room work an independent chuck is frequently 
used for holding irregular shapes, the workman set¬ 
ting up the piece in the jaws approximately to the 
center which is to be bored or drilled and then using 
an indicator on the work to indicate the exact center. 
Such a chuck is shown at Q in Figure 58. It will be 
seen that this chuck is indispensable both in the 
tool-room and for general manufacturing for holding 
irregularly-shaped pieces on the turret lathe or on the 
boring mill. When a number of pieces of the same 
kind are to be chucked one after the other, and when 
these pieces cannot be held by the ordinary three- 
jawed, geared, scroll chuck, it is customary to set 
two of the jaws, or more if possible, to the proper 
center to act as a vee in locating the teeth. The 
work is then placed in the chuck with the proper sur¬ 
faces against the two fixed jaws, and the other jaws 
are brought up independently. The construction of 
this chuck is clearly indicated in Figure 58. The 
jaws are moved radially by the screws, S, which in 
their turn are controlled by a socket wrench (not 
shown in the illustration). The body of the chuck 
is generally fastened to a faceplate, as shown at T, 
which is screwed to the nose of the spindle. The 
face of the jaw is provided with a series of notches, 
so that a special jaw of any particular kind can be 
easily attached to it. As ordinarily furnished, the 
chuck is supplied with one or more sets of jaws 
stepped out at different diameters, so that a variety 
of work can be held without recourse to special jaws. 


134 


TOOLS AND PATTERNS 



FIG. 59. MANUFACTURING AND MACHINE VISES 


Machine and Manufacturing Vises. —The impor¬ 
tance of the proper way of holding a piece of work 
to be machined cannot be overestimated. Hence, 
vises are used on many classes of machines for hold¬ 
ing work during the process of machining. They are 
particularly useful on the milling machine and the 
drill press; and recent developments along these 
lines have developed a particular type of vise called 
a manufacturer’s vise. This vise is more or less 
adaptable, and suitable stops can be applied and 
locating pins put in for the purpose of locating a 






MACHINE EQUIPMENT 


135 


small number of pieces and holding them securely. 
Attachments provide for drill bushings of different 
sizes, and drill plates to hold the bushings can be 
applied with little trouble. The Graham Manufac¬ 
turing Co. makes a useful tool of this kind, as shown 
at A, B, and C, Figure 59. The upper figure, A, 
shows the vise supplied with special jaws, D, and a 
drill plate of an adjustable type, E, which can be 
moved to any desired location over a piece of work 
held in the vise jaws. The figure, B, shows another 
plate applied to the same type of vise; the work, F, 
is held between the vise jaws and obtains its endwise 
location against the stop, G, which is likewise adjust¬ 
able. A third application of this vise is shown at C, 
where a set of special jaws of V-type are used to 
center a piece of round work, and the drill plate is 
set centrally so that the vise can be used as a cen¬ 
tering jig. 

An excellent type of machine vise employing a cam 
as the locking principle is shown at H, Figure 59. 
This vise, made by the F. C. Sanford Manufacturing 
Co., is an excellent example. It can be used as an 
ordinary vise and adapted to special conditions with 
standard jaws, as shown at K, or these jaws can be 
made up in special form to suit particular cases. 
Approximate location of the jaws is obtained by 
means of the screw, L; after the location has been 
obtained the entire locking movement is made by the 
lever, M, which is eccentrically placed with relation 
to the link, N, by means of which the jaw is locked. 
Manufacturing vises of this type are coming more 
and more into use and several varieties are on the 


136 TOOLS AND PATTERNS 

American market. They are made in a number of 
styles and sizes to suit different conditions. 

The ordinary machine vise commonly found on the 
milling machine, also useful in drill press work, is 
shown at 0, Figure 59. This type of vise is operated 
by a sliding jaw, controlled by a screw which, in 
turn, is manipulated by the handle, P. This vise is 
made by the Brown & Sharpe Mfg. Co., and can be 
provided with false jaws to hold special forms of 
work, as indicated at Q. A vise of this sort is found 
in every tool crib, usually in several sizes. 

Taps, Dies, and Holders.— The ordinary method of 
cutting a thread on the outside of a single piece of 
cylindrical work is to “chase” it on an engine lathe 
with a single-point tool, gearing up the lathe to the 
proper pitch, or number of threads per inch, and 
taking several cuts successively upon it until the 
desired depth has been reached. When a hole of odd 
size is to be threaded in a piece of work, the same 
method may be employed, but the type of tool used 
is one adapted to internal cutting. Both procedures 
may be used with success, but they are uneconomical 
unless the work is of particular accuracy and difficult 
to get at with some other types of threading tools. 
A properly equipped tool crib should be provided 
with complete sets of taps, dies, chasers, and suitable 
holders for them, so that any type of standard thread 
can be cut without difficulty. If the thread to be cut 
is difficult of access, the lathe method may be the only 
one possible. 

Figure 60 shows, at A, a standard type of hand 
tap which is commonly used in connection with a 


MACHINE EQUIPMENT 


137 



wrench, B, for tapping out a hole by “man power.” 
The tap itself is squared on one end so that it can 
he readily held in the adjustable jaw, F, by a turn 
of the threaded handle, G. The same taps are also 
used in a releasing tap holder when used on a turret 
lathe or a hand screw machine. The ordinary type 
of spring threading die, shown at C, in the same 
illustration, is commonly used in a die holder such 
as that indicated at D. Such a die is used for thread¬ 
ing screws, studs, or other cylindrical work, either 
by hand or by a screw machine 5 the holder, I), being 
used when the work is done by hand. A special type 
of holder is used on the screw machine, which is of 
the releasing variety such as that used for holding 
a tap on the same machine. 

If the taps and dies mentioned are used on a screw 
machine or turret lathe, it is necessary to reverse 
the machine in order to back off the tap from the 












138 


TOOLS AND PATTERNS 


work after the thread has been out. So also, the 
spindle on the engine lathe must be reversed in cut¬ 
ting a thread and the tool run back out of the way. 
(The more modern varieties of engine lathes are 
provided with a form of indicator which makes a 
reversal of the spindle unnecessary.) Naturally a 
considerable loss of time is entailed by this oper¬ 
ation, and in order to overcome it another type of 
die head, called an opening die, can be used, whereby 
it is unnecessary to reverse the spindle. An opening 
die of this sort, E, Figure 60, is made by the Geo¬ 
metric Tool Co. It can be supplied with chasers, K, 
which may be made for any form or pitch of thread 
within the capacity of the die head. The chasers 
accurately fit slots cut to receive them in the face of 
the die head, as indicated in the illustration. 

In operation, when used on a turret lathe or hand 
screw machine, the shank, L, is held in the turret 
and the open end, containing the chasers, is fed onto 
the work until a predetermined stop has been reached, 
at which time the chasers fly open and permit the 
die head to be drawn back out of the way. These die 
heads are extremely useful in manufacturing work. 
Although their first cost is high, the fact that a single 
size of holder can be used for many sizes and varieties 
of threads by the simple substitution of a different 
set of chasers, makes it an economical proposition in 
the machine equipment. 


CHAPTER X 


FIXTURES FOR PLAIN AND STRADDLE 
MILLING 

Nature and Variety of Fixtures.— The process of 
milling has taken the place of planing to a great 
extent in the general processes of interchangeable 
work, except in cases where the size of the piece is 
too large to be handled to advantage on a milling 
machine, or when the accuracy required, or the shape 
of the piece is such as to make it impossible to mill 
the surface. There are a number of different types 
of machines which are adapted to the milling process 
and it naturally follows that the type of milling fixtures 
which are used on the various machines must he so de¬ 
signed that they will apply to the particular type on 
which the work is to be done. Thus, if a piece of 
work is to be handled on a milling machine having a 
horizontal spindle, the fixture will be so designed as 
to present the work to the cutter revolving in the 
same way that a carriage wheel turns. Or again, if 
a fixture is to be used on a milling machine having a 
vertical spindle, the fixture must he so designed as 
to present the work to the cutter revolving in a hori¬ 
zontal plane, like a top. 

The two most important types of milling machines 
used in manufacturing are those having a horizontal 
139 


140 


TOOLS AND PATTERNS 


spindle and those with a vertical spindle. Variations 
of these types are found in those that have more than 
one spindle, such as duplex machines and multiple- 
spindle machines. In the duplex type, the spindles 
are opposed and can be adjusted towards each other 
until the ends of the cutters strike. The multiple- 
spindle machines have from four to seven spindles, 
some of which are arranged horizontally and others 
vertically. 

It is evident that in the design of any milling fix¬ 
ture, the first point to be taken into consideration is 
the nature of the work and the material to be cut. 
The next point is the type of machine which is best 
adapted to the work; and the third point is the 
method of holding the piece when it is being machined. 

Necessity for Proper Holding. —The most important 
point in connection with the design of milling fix¬ 
tures is the proper holding of the work; for it must 
not be distorted by the pressure of the clamp used 
in holding it in place and, at the same time, the 
method of clamping must be so rigid that there will 
be no possibility of “chatter” which would result if 
the work were allowed to swing out of position under 
pressure of the cut. In this matter of holding, the 
ingenuity of the tool designer is the important fac¬ 
tor, also, the lift or dragging action of the cutter 
while it is engaged with the work must be considered. 

A piece that has previously been partially ma¬ 
chined, with either holes, slots, or other finished sur¬ 
faces, will naturally require different holding methods 
than those used for rough castings or forgings. For 
in performing a second or third operation on a piece 


FIXTURES FOR PLAIN AND STRADDLE MILLING 141 

of work, it is essential that the location should be 
positively determined by one of the finished surfaces. 
Which surface is to be used as a locating point must 
be determined by the nature of the work and the 
sequence of the various operations upon it. Let us 
assume, for instance, that a lever having a boss at 
each end has been drilled and reamed at one end 
through the boss, and that the other end is to be 
“straddle-milled .’ 9 It is obvious, then, that in order 
to locate the piece properly so that the second milled 
surface on the boss will be at right angles to the hole, 
the work must be located by a stud in the hole, and 
must be set up on the fixture in such a way that the 
clamps will not spring it out of alignment. 

In work that has not been previously machined and 
is still in the rough state, the locating points must 
be so placed as to center the work in relation to the 
cut which is to be taken for the greatest degree of 
profit. 

Milling Fixture for a Connecting Rod.— An excel¬ 
lent example of a milling fixture designed to handle a 
drop forging of an automobile connecting-rod is shown 
in Figure 61, the work being shown at A, and the sur¬ 
face which is to be milled being the small end-boss, B. 
In this milling operation, which is called straddle 
milling, two cutters of the side-milling type, C, are 
set up on an arbor, D, and are properly spaced with 
a collar between them so as to make the distance 
between the cutting, edges of the two cutters the 
same width as the thickness of the boss to be milled. 
In the example shown, the boss, B, is located in a 
V-block, E, the angular surfaces of which tend to 


142 


TOOLS AND PATTERNS 



FIG. 61 . SIMPLE STRADDLE-MILLING FIXTURE FOR A 
CONNECTING ROD 


center the boss correctly. The large end, F, is 
dropped down upon a locating pin, G, in the base of 
the fixture, and two side stops in the form of pins, 
H, are set into the lug, K, which is a part of the 
fixture base. The upper portion of this lug is pro¬ 
vided with a set-screw, L, which acts upon the small 
boss, B, to hold it firmly down in the V-block. A 
cam lever, M, works against the side of the connect¬ 
ing rod and throws the piece over against the two 
pins, H, which give the work its location. 

A fixture of this kind may be manipulated very 
rapidly; the design is extremely simple and can be 
made cheaply. In addition to this, the method of 
holding the work and supporting it under the cut is 
so rigid that there is no likelihood of chatter. Such 
a fixture can be made up to hold a couple of pieces 
if desired, in which case two gangs of milling cutters 
















FIXTURES FOR PLAIN AND STRADDLE MILLING 143 



FIG. 62. DOUBLE-STRADDLE MILLING FIXTURE FOR AN AUTOMOBILE 
CONNECTING ROD 


would be required. All milling fixtures are provided 
with keys such as those shown at N, and are also 
slotted, as at 0, so that they can be held down on the 
table of the milling machine by means of T-bolts. 

Straddle Milling Fixture Working from a Finished 
Surface. —The connecting-rod shown in Figure 61 is 
an excellent example of another type of fixture. Let 
us assume that after the first operation has been 
done, a hole is drilled .and broached to size in the 
boss, B. After this operation it becomes necessary 
to mill the other end of the connecting-rod, using the 


















































144 


TOOLS AND PATTERNS 


hole in the smaller boss as a locating point. In this 
manner the large boss, F, can be milled accurately at 
right angles to the hole. Referring to Figure 62, the 
method of setting up for this operation will be clearly 
understood. The plan view above shows two connect¬ 
ing rods, the small bosses of which have been milled 
with holes drilled and broached in the manner just 
described. 

In the first place, the bosses, B, in the small end 
have plugs, Q, inserted in them which snugly fit the 
holes. These plugs rest in two pairs of V-blocks, E, 
for purposes of alignment, and the V-blocks are fin¬ 
ished on the surfaces, P, so that the sidewise location 
is assured. The other end of the work which is to be 
machined drops down upon the finished pad, R, on 
the base of the fixture. When the connecting-rods 
are to be clamped in place on the fixture, the strap, 
S, is placed across the two rods and the nut, T, is 
tightened, thus securing the work firmly. A coil 
spring, U, is placed under the clamp in order to 
assist in raising it when the work is being removed 
from the fixture. 

It will be seen that this method of locating from a 
finished hole, and also the method of clamping with a 
strap across both pieces, makes it possible to set up 
the work without any fear of distorting it or throw¬ 
ing it out of alignment. Fixtures of this kind are in 
common use on many varieties of work and can be 
applied to other instances in which the same prin¬ 
ciple is involved. Both of the fixtures shown in 
Figures 61 and 62 are adapted for use on a horizon¬ 
tal type of milling machine. 


FIXTURES FOR PLAIN AND STRADDLE MILLING 145 

Gang Milling.—In milling several surfaces of vary¬ 
ing depths on any piece of work, if the production 
is sufficient to warrant the work being done in a 
single operation with a gang of special cutters, a 
fixture should he designated so that the cutters may he 
mounted on an arbor to obtain the proper spacings 
and depths. A good example is shown at A, Figure 
63. 

In this case the work has several shoulders and 
several plane surfaces of different heights, as shown 
in the illustration. The milling fixture is of ex¬ 
tremely simple type, and is nothing more nor less 
than a east-iron block, B, grooved and finished at 
C and D to give the proper location to the work in 
relation to the table. A set-screw, E, or several set¬ 
screws, according to the length of the work, is used 
to clamp it against the surface, D. An important 
feature in the design of any sort of milling fixture 
in which the work is located against finished sur¬ 
faces, is the groove, F, the purpose of which is to 
allow any dirt or chips which might accumulate in 
the fixture to be swept out of the way and passed 
down into the groove so that they will not interfere 
with the location of the work. The cutter gang, 
shown at G, H, I, J, and K, is so arranged that it 
will give the proper spacing and depth. Many varie¬ 
ties of work can be handled with a set of cutters of 
similar character to these, and the work can be pro¬ 
duced at a rapid rate and within good commercial 
limits of accuracy. 

End Milling a Slotted Bracket.— It is frequently 
necessary in the process of manufacturing to cut a 


146 


TOOLS AND PATTERNS 



slot in a easting or forging which will bear a certain 
relation to some other finished surface. An example 
is shown in Figure 63 at L. In this example the 
bracket, M, has been previously machined at the side 
and base, and it is now necessary to cut the slot, N, 
in a certain relation to these two surfaces. The 
method of setting up the work in this case is very 








































































FIXTURES FOR PLAIN AND STRADDLE MILLING 147 

simple, as the fixture itself consists of an angular 
plate, O, which is fastened down to the milling ma¬ 
chine table in the usual manner. The work is located 
on the finished pad at the base and against the side 
surface, being clamped in position by means of the 
two bolts shown. The cutter which is used for this 
work is a spiral end mill, P, which is clearly shown 
in the fixture. In operation, the table feed of the 
milling machine is started and the work is run di¬ 
rectly by the cutter at the position indicated. 

Fixture for Angular Milling.— Taking as an ex¬ 
ample the same bracket shown at L, let us assume 
that an angular surface, Q, is to be milled upon it in 
another operation, bearing a certain relation to the 
previously finished surfaces. A piece of work of this 
kind may be handled in three different ways, but in 
order to make the application of the milling machine 
more clearly apparent, let us assume that in this case 
a horizontal type of machine is used which has a 
vertical milling attachment that can be swung to any 
desired angle. The procedure then would be to set 
over the vertical attachment to the desired angle of 
the finished surface, Q, and to locate the work hori¬ 
zontally as in the preceding instance, using a type 
of fixture shown at R, with suitable locaters and 
clamps. A milling cutter of the spiral end-mill type 
is inserted in the milling attachment as indicated at 
S, and the machine table is fed under the work while 
in the position indicated. 

Another method of handling the same piece of work 
would be to build the fixture itself on an angle with 
the table, so that the surface, Q, which is being milled. 


148 


TOOLS AND PATTERNS 


would lie parallel to the table itself. In such a case, 
an ordinary type of plain milling cutter would be 
used, the cutter having straight cutting edges parallel 
to the surface of the table. The work could also be 
performed in the same fixture as that shown by 
swinging the vertical milling attachment to another 
angle and using the end of the mill for making the 
cut, instead of the side of the mill as indicated in the 
drawing. 

Fixture for Form Milling. —Let it be assumed that 
a piece of work, T, is to be formed to the contour 
shown. The work has been previously machined 
along the base, U, but has not been surfaced on the 
edges. It is necessary to reduce the form that is 
parallel to the lower surface and approximately in 
line with the edges of the work. 

In this case the fixture, V, is of U-section, bolted 
to the table in the usual manner, and located by 
means of tongues in the table T-slots. Two adjust¬ 
able studs, W, are furnished along the side, and 
against these studs the rough side of the work is 
located, being clamped firmly against it by means of 
the thumb-screws, X. It is customary, in work of 
this kind, either to build a fixture which will take a 
number of pieces of the same kind, or else to make 
the work in a single strip and cut it up into pieces 
of the desired length after it has been machined. 
Naturally, the process which is to be used determines 
the method of holding and clamping. The formed 
milling cutters, Y, and side milling cutters, Z, are 
made up to suit the contour of the work to be manu¬ 
factured. 


FIXTURES FOR PLAIN AND STRADDLE MILLING 149 


- M 



FIG. 64. DOUBLE INDEXING FIXTURE FOR STRADDLE MILLING 
LEVERS 

Index Milling a Pair of Levers— When rapid pro¬ 
duction is desired on a piece of work it may be pos¬ 
sible and profitable to arrange a fixture similar to 
that shown in Figure 64. Here we have two levers 
of identical size, but the bosses on the ends are of 
two different widths. They can be machined in a 
single setting by a suitable arrangement of the fix¬ 
ture and cutter. In the case shown the levers have 
a boss at one end, as at A, and at the other end, as 
at B. The fixture is built so that it will hold the two 
levers in such a way that a large and a small end are 
successively presented to the cutters at A and B, and 
these cutters are spaced so as to mill different widths 
according to the thickness of the bosses. 

The fixture locates the work in each case against 
the small set-screws, C, to give sidewise location 
against the sides of the lever, and suitable V-blocks, 
D, hold the bosses centrally. The V-blocks are at one 


































150 


TOOLS AND PATTERNS 


end only, the other ends rest against the angular sur¬ 
face, E. Thumb-screws, F, are provided on each side 
of the fixture to hold the work against the set-screw, 
C. A rocking clamp, G, on each of these set-screws 
equalizes any variation in the forging and makes the 
clamping action positive. An ordinary strap clamp, 
H, holds the work down on the fixture. 

The method of using the fixture is to mount it suit¬ 
ably on a base, such as that shown at K, centering it 
by means of a central plug, L. The base is fastened 
down to the table of the milling machine, but the 
upper portion, M, can be swung around through an 
arc of 180 degrees so as to present the opposite ends 
of the levers to the cutters in sequence. Indexing is 
usually performed manually by the operator with 
some type of locating pin which gives the correct 
location when indexing from one position to another. 
A scheme for accurately indexing a piece of this kind 
will be described under the next heading. The fore¬ 
going fixture mills two ends of two bosses at the 
same time and is then indexed to mill the two oppo¬ 
site ends, so that four ends of the two levers have 
been machined at a single setting. But it must be 
recalled that a fixture of this kind is not economical 
unless a number of pieces are to be machined. 

Index Milling Fixture for Quantity Production.— In 
work that is being put through a shop on the inter¬ 
changeable system, as in automobile production or 
other manufacturing where a number of pieces of the 
same sort are to be successively machined to a given 
size, a number of pieces are usually found which re¬ 
quire some sort of an indexing fixture for milling 


FIXTURES FOR PLAIN AND STRADDLE MILLING 151 



slots, clutch teeth, and the like. The progressive de¬ 
signer of tools, therefore, usually designs some sort 
of universal milling fixture which has sufficient flexi¬ 
bility that it can he adapted to such a variety of 
work. 

For example, while supervising the work on a large 
automobile plant equipment for a Russian corpora¬ 
tion, I used recently the type of fixture shown in 
Figure 65 over twenty times on as many different 
cases. The indexing mechanism and the base of the 
fixture were practically the same in every case; the 
only differences were in the number of points of in¬ 
dexing and in the adapters which were used to hold 
the different shapes to he milled. A particular ad¬ 
vantage in this type of fixture is its adaptability to 
different conditions, and also to the fact that it is 
practically impossible to destroy the correct indexing 
































152 


TOOLS AND PATTERNS 


of the fixture, as the mechanism is so well protected 
from chips and dirt that no trouble can be caused 
thereby. As this fixture is so notably flexible, it is 
worth while to describe it in greater detail than 
might otherwise be deemel necessary. 

The base of the fixture, A, is fastened to the milling 
machine table by the bolts shown, being located in 
the usual manner by keys in the table T-slot. A 
revolving table, B, is suitably mounted on a stud, C, 
in the center of the base. On the under side of the 
table a hardened tool-steel indexing ring*sjil, is se¬ 
curely fastened by means of screws, and is ^provided 
with angular slots, F, around its periphery, as many 
in number as the indexing points which are to be 
made. A sliding block, G, is located radially in rela¬ 
tion to the index plate and is tapered oiTidie end 
which fits the angular slot in the index plate, thus 
determining the radial indexing points on the fixture. 
The movement of this sliding block is controlled by 
a handle, H, and it is drawn back into position by 
the spring, K, when the proper indexing point has 
been reached. It will be seen that the location of the 
slots in the index plate is such that it is practically 
impossible for any chips or dirt to interfere with 
the proper location of the table. The upper part 
of the fixture can be fitted with adapters of different 
kinds to hold various shapes or forms which are to 
be milled. 

The work shown in the illustration is a cylindrical 
piece, L, which is squared up at the upper end by the 
two milling cutters, M. This piece of work is located 
on a spring stud, N, expanded by means of the bolt, 


FIXTURES FOR PLAIN AND STRADDLE MILLING 153 


0, so that all chance of vibration is taken np and 
there is no possibility of chatter during the progress 
of the work. A hand lever, P, is provided on the 
table to index it from one position to the other; but 
this feature is unnecessary in many cases as the 
workman can use the work as a lever for indexing 
the table. However, a series of holes around the per¬ 
iphery of the table allow the pin to be inserted at 
different points to provide for a circular indexing 
movement when needed. This type of fixture is prob¬ 
ably one of the most useful that can be made to 
handle a great variety of work, and although its first 
cost is fairly high it should not by any means be con¬ 
sidered an expensive fixture. 


CHAPTER XI 


FIXTURES FOR CONTINUOUS MILLING 

The Value of Simplicity.—It is an economical 
proposition, when a great number of pieces of the 
same kind are to be machined by the process of mill¬ 
ing, to make the fixtures wherever possible in such a 
way that there will be as little lost time as possible 
caused by taking out and putting in the work. It is 
most advantageous to arrange a milling fixture in 
such a way that the cutters will be working as nearly 
continuously as possible. Several methods can be 
employed, depending upon the class of work to be 
done and the machine which is used for the work. 
On the regular type of horizontal milling machine 
some classes of work can be handled in an almost 
continuous manner; although the cutting action will 
not be absolutely continuous, there is very little lost 
time between cuts and it is unnecessary to stop the 
machine at any time. 

< A special type of milling machine, called a con¬ 
tinuous miller, is made by the Becker Milling Ma¬ 
chine Company. This machine uses a revolving table 
and a series of fixtures arranged radially on the table. 
The Potter and Johnston Company also make a con¬ 
tinuous milling machine having an indexing table on 
which the work can be set up on one side of the table 

154 


FIXTURES FOR CONTINUOUS MILLING 155 



FIG. 66. SIMPLE TYPE OF CONTINUOUS MILLING FIXTURE 

while another piece is being machined on the oppo¬ 
site side. The Beaman and Smith Company make a 
large machine with seven spindles which can be used 
for continuous milling on large work. These various 
machines require somewhat different types of fixtures 
because of their different arrangement of spindles. 

In selecting the simplest of continuous milling fix¬ 
tures, let us look at the one shown in Figure 66, 
which is made for a horizontal milling machine. The 
work in this case is a bracket, A, shown in the upper 
part of the illustration. The bracket is to be straddle 
milled by a gang of cutters, as shown at B, which 
are used to face the sides of the bosses as indicated 
in the upper part of the illustration. The fixture base, 
C. is located on the table of the milling machine in 
the usual manner and has at each end a simple type 
of locating and clamping device in which the work 







































156 


TOOLS AND PATTERNS 


is located and held. A sectional view of the arrange¬ 
ment is shown at the left-hand portion of the figure. 
The other end is identical with it. The work is 
placed in the position shown, resting against the stop 
pins, D, and is clamped in place by means of the 
screw, E, at the top of the fixture and by the clamp, 
F, at the bottom. The latter clamp is operated by 
means of the thumb nut, G, and is released by the 
coil spring, H. 

In operation, the work is placed in position and 
clamped on one side of the fixture; the table is then 
moved inward close to the revolving cutter, and the 
feed is set in operation. While the table is moving 
forward and the piece in position is being milled, the 
operator places another piece of work in position and 
clamps it at the other end of the fixture. Then, after 
the work at one end has been completed, the table is 
moved over to machine the other piece; the first piece 
is removed from the fixture and another one is in¬ 
serted in its place. By this description it will be 
seen that the process of milling is nearly continuous, 
and for certain classes of work this fixture can be 
used to good advantage. 

Continuous Milling Fixture for Cylinders. —The 

Beaman & Smith continuous milling machine makes 
possible the machining of surfaces of large size in 
such a way that the action of the cutters with prop¬ 
erly designed fixtures, is practically continuous from 
the time the machine starts in the morning until the 
factory closes at night. The construction of the 
machine is such that there are a number of tables 
similar to, but somewhat shorter than, a planer 


FIXTURES FOR CONTINUOUS MILLING 157 



FIG. 67. CONTINUOUS MILLING FIXTURE FOR AUTOMOBILE 
CYLINDERS 

table, and each of these tables can be equipped with 
a similar set of fixtures. These fixtures can be 
loaded one after the other and placed in engage¬ 
ment with the feed mechanism of the table, one fix¬ 
ture following the other closely with very little space 
between. The fixtures pass through the machine 
from one end to the other, the finished work is then 
taken off and is replaced by other pieces, after which 
the entire table with the fixtures mounted on it is 
carried around to the original starting point and 
started again on its journey through the machine. 
For some classes of work four or five of these tables 
may be required, each with the same type of fixture 
upon it. In milling the cylinders, transmission cases, 
and crank cases of automobiles, as well as in other 


























































158 


TOOLS AND PATTERNS 


work of similar character, the production which can 
he obtained from a machine of this kind is extremely 
high. Under favorable circumstances from 300 to 400 
automobile cylinders of 4%-inch bore can be produced 
in a ten-hour day. 

A good example of a continuous milling fixture 
for automobile cylinders is shown in Figure 67. The 
cylinders, A, are to be milled on the surfaces, B and 

C. They have been previously machined on the end 

D, and in the bore. The cylinders are located on 
plugs, E, shown dotted in the bore of the cylinder. 
Each fixture is capable of holding six cylinders at 
one time. The fixtures are held down on the table 
by means of clamps and T-bolts in the T-slots, and 
the work is held down on the fixture by means of 
the clamps shown at F and G. In the case shown 
two milling cutters operate on the upper part of the 
cylinders and two more opposed to each other are 
used to machine the surfaces on the sides. 

Fixture for * ‘Becker' ’ Continuous Milling Machine. 
—The Becker type of continuous milling machine uses 
a revolving table which is in continuous operation 
after the first pieces have been set in place on the 
fixture. The fixture, shown in Figure 68, is built 
to accommodate twelve wall bearings, as seen at A. 
These bearings are located in position by the fixed 
studs, B, which act as a vee, into which the pieces 
are forced by means of the sliding V-block, C, oper¬ 
ated by the thumb-screw, D. 

After the first pieces have been placed in the fix¬ 
ture, the operator simply removes the finished work 
and continues to place new pieces in the position 


FIXTURES FOR CONTINUOUS MILLING 159 



FIG. 68. CONTINUOUS MILLING FIXTURE FOR BECKER MILLING 
MACHINE 


occupied by those just finished. It will be seen that 
as the cutter, F, is in continuous movement, it has a 
contact with several pieces at the same time. In the 
case illustrated the work is of such nature that there 
is very little “dead time,” or time when the cutter 
is not in contact with the work. This example, there¬ 
fore, is an excellent one to show the value of con¬ 
tinuous milling and how it can be applied to manu- 











































160 


TOOLS AND PATTERNS 


facturing work. However, when the shape of a piece 
of work is such that it cannot he set up on a cir¬ 
cular fixture without leaving wide spaces between 
the pieces, it is not advisable to attempt to mill it 
by the continuous milling process; but with work 
that can be set close together, it is usually highly 
profitable. 

Spline-Milling Fixtures. —Some years ago the cus¬ 
tomary method of cutting a slot in a shaft for a key¬ 
way was to drill a hole at each end of the slot and 
then mill from one hole to the other. This process, nec¬ 
essarily, was somewhat slow, and it has been largely 
replaced by some form of spline-milling machine or a 
spline-milling attachment applied to a plain milling 
machine. 

The machine that is manufactured by the Pratt 
& Whitney Co. for this purpose consists of two 
opposing spindles arranged in such a way that they 
feed automatically towards each other during the 
process of the work. The table is reciprocated, with 
the work in position on it, to a specified length of 
stroke determined by the length of the key-slot. The 
fixtures used for this machine may be those which 
hold a single piece for cutting two slots opposite 
to each other, or it may be arranged to hold several 
pieces in which one or more slots are to be cut. 

Spline-milling machines are well adapted for all 
kinds of rectangular key slotting, unless the work 
to be done is of such a size as to be prohibitory. For 
all kinds of shafting, arbors, and similar work, it 
can be arranged without the necessity for any elab¬ 
orate fixture. In some cases, however, in order to 


FIXTURES FOR CONTINUOUS MILLING 161 



increase production, fixtures may be made to suit 
particular cases. 

A spline-milling attachment for a hand-milling 
machine, made by the Standard Engineering Co. to 
apply to one of their hand milling machines, is also 
very useful for milling key-slots, although but one 
cutter is used at a time. The attachment is pro¬ 
vided with automatic features which make it val¬ 
uable for many kinds of manufacturing. In the at¬ 
tachment mentioned, the spindle is vertical in rela¬ 
tion to the table of the machine. On the spline¬ 
milling machine, however, the two spindles lie in a 
horizontal plane. 

Let it be supposed that a piece of work, such as 
that shown at A, Figure 09, is to be splined or cut 




















162 


TOOLS AND PATTERNS 


on the end with four keyways, as indicated at B in 
the end view. This piece having the four slots at 90 
degrees apart on the periphery, requires some sort 
of indexing fixture in order that the various slots 
may be cut in their proper relations to each other. 
The illustration shows the method of holding used 
for this fixture when applied to a Pratt & Whitney 
spline-milling machine. The fixture base is fastened 
to the milling machine table by means of bolts 
through the slot, C, at each end of the fixture, and is 
aligned by means of keys entering the table T-slot. 
The method of locating the work on this fixture is 
out of the ordinary, and is therefore worthy of a 
detailed description. 

The two shafts, shown at D and E, are laid on the 
finished surface of the fixture. They are held by the 
clamp, F, the angular portion of which grips and 
pulls in on the cylindrical part of each shaft. As the 
clamp screw is set up, the two shafts approach each 
other until they strike against the finished surfaces 
or shoulders on two inserted pieces, G and H, which 
locate and align the work. The first cut on the key- 
ways is made with the pieces set in the position 
shown, after which the clamp is released sufficiently 
to permit the two shafts to be turned with the slot 
downward. A positive method of locating from the 
first slot which has been cut is provided in the bed 
of the fixture; and as the shaft is revolved after the 
first cut and stands with the slot downward on the 
fixture, this locater engages with the slot and gives 
positive location. The locaters are controlled by the 
set-screws, L. 


FIXTURES FOR CONTINUOUS MILLING 163 

It will be seen that a repetition of the indexing 
process will produce the four slots at 90 degrees 
from each other without the need of expensive fix¬ 
tures ordinarily used for this work. Other examples 
of spline-milling fixtures will be given, but as they 
are usually of a simple form which can be made up 
at minimum expense, it is unnecessary to go into the 
matter more completely here. 


CHAPTER XII 


FACE-PLATE FIXTURES 

Fixtures for Single Pieces. —In the general process 
of manufacturing, and also in tool-making, many 
pieces of work to he machined on an engine or tur¬ 
ret lathe cannot he satisfactorily held in any of the 
various forms of chucks previously described. For 
such cases either a face-plate of standard form is 
used, as that shown in Figure 70, or, if a number of 
pieces are to he machined, a special face-plate with 
suitable lugs and clamps may he made up. When 
required for toolmaking, or for a single piece of 
work, the standard style of face-plate in Figure 70 
is commonly employed. This type is made of cast 
iron and is screwed to the end of the spindle of the 
machine. 

If the toolmaker has a certain piece of work to 
bore, and the work is of such size that it can he 
clamped upon the face-plate, he would set up the 
work against the face of the plate, A, and apply 
suitable clamps through several of the slotted holes, B, 
so that the work could he held in the desired posi¬ 
tion for machining the hole. In setting up a piece 
of work of this kind he would use an indicator on 
the work to determine when it was in the correct 
position for machining. The T-slots, C, can he used 
164 


FACE-PLATE FIXTURES 


165 



FIG. 70. STANDARD FACE PLATE FOR AN ENGINE LATHE 


both to hold the work and to fix steel blocks in cer¬ 
tain locations on the face of the plate when several 
pieces of the same kind are to be machined. Such 
a face-plate is seldom used in general manufacturing 
except for the work just described. 

Fixtures for Quantity Production. —We now come 
to the class of manufacturing known as quantity pro¬ 
duction, where many pieces of the same kind are 
produced. If a number of pieces are to be machined, 
it is obvious that the face-plate fixtures to be used 
can be made up with quick clamping attachments 
which require a minimum amount of time and labor 
to set up. They can also be made with simple clamp¬ 
ing arrangements which answer every purpose for 
holding the work but which take a little longer in 
setting up. The latter fixtures are, of course, some¬ 
what cheaper than the more elaborate, and if the 
output is to be comparatively low, they will answer 
every purpose. 




























166 


TOOLS AND PATTERNS 



The fixture, A, Figure 71, is shown holding the 
work, B, a flanged collar which has previously been 
machined on its inside surface, C. As it is neces¬ 
sary to cut out the recessed portion, D, of the collar 
in a subsequent operation, the work is located on the 
stud, E, and is clamped in place on the locating stud 
against the face of the fixture by means of the 
clamps, F, three in number arranged equidistantly 
on the face of the plate. In a fixture of this kind 
the revolution of the work around the axis of the 
spindle, G, is perfectly true, so that when the recess, 
D, is cut it will be concentric with the previously 
machined surface, C. 

Fixtures for Cutting Packing Rings.— The other 
example of a face-plate fixture, H, Figure 71, is de¬ 
signed to handle a ring pot, K, from which packing 
rings are to be cut. The ring pot has previously 
been faced on the end shown against the face-plate 
and three holes have been drilled in the flange for 
locating and driving purposes. The work is set up 




































FACE-PLATE FIXTURES 


167 


on the face-plate fixture, locating on the pins, L, one 
of which is shown in the illustration. The work is 
clamped back against the face of the fixture by means 
of three hook bolts, M, having an angular end which 
engages with the angular flange at N, thus holding 
the work back firmly against the face of the plate. 
This face-plate is provided with a bushing, 0, in 
which the pilot, P, of the boring bar is guided. The 
boring bar is used to bore out the inside of the pot, 
as indicated. When a number of packing rings are 
to be made up a fixture of this kind can be used to 
advantage or the flange of the pot can be made so 
that it can be gripped in chuck jaws of special form. 
The latter method is more common at present and is 
superior to that shown, due to the fact that no pre¬ 
liminary operation is necesary on the work before 
this machining operation. 

Face-Plate Fixture for a Hub Flange.— The face¬ 
plate fixture shown in Figure 72 is somewhat similar 
to that noted at A, in Figure 71; but in this case 
the work is located by an outside surface which also 
has been previously machined, shown at A in this 
illustration. The face-plate, B, is screwed to the end 
of the spindle as indicated, and is recessed to allow 
the shoulder, A, to fit into it, thus giving the correct 
location. The flange, C, has been drilled in several 
places, as indicated at D, and these drilled holes are 
used for driving against the pressure of the cut, by 
means of the pins indicated. The clamps, E, three 
in number, hold the work back against the face of 
the plate, and are slotted to allow them to be drawn 
off the flange when setting or removing the work 


168 


TOOLS AND PATTERNS 



from the fixture. The coiled springs, F, are pro¬ 
vided in order that the clamps will always stand 
away from the work when it is being placed in position. 
Fixtures of this kind, largely used in the general 
process of manufacture, can be adapted to many 
kinds of turret lathe work. 

Self-Centering Fixture for a Rough Casting. —It is 
sometimes desirable to machine a piece of work, a 
ring pot, for instance, whose shape is such that it 
is not readily held in chuck jaws. A fixture for this 
purpose is shown at A, Figure 73. The casting, B, 
is somewhat thin in section, and is to be bored and 
turned by means of the tools, C and D. As no 
previous machining has been done on the casting, it 
is necessary to center it from the rough surface in 
some way and to clamp it'firmly on the fixture. 

For the purpose of centering the work, a spring 
tapered plug, E, is located in the fixture in such a 


































FACE-PLATE FIXTURES 


169 



FIG. 73. SECTION THROUGH A SELF-CENTERING FIXTURE FOR A 
RING POT 


way that it automatically centers the work from the 
inside. The spring at the base of the plug permits 
the clamps, F, to be tightened down upon the face 
of the flange, so as to grip the work securely. While 
the spring plunger centers the work, it does not in 
any way prevent the tightening of the clamps, and 
also it is bored out and ground to the size of the 
pilot, G, of the boring bar in which the cutter, D, is 
located. The principle used in this fixture can he 
applied to a variety of work on turret lathes and 
boring mills. 

Fixture for Thin Aluminum Castings.— The in¬ 
stances which have been previously noted have all 
been pieces of cylindrical section, but it frequently 





































170 


TOOLS AND PATTERNS 



FIG. 74. FACE-PLATE FIXTURE FOR A THIN ALUMINUM CASTING 


happens that the work which is to be machined is of 
irregular form requiring special arrangements for 
locating and holding it. One point in the design of 
face-plate fixtures for such work, is that the piece 
shall be held in such a way that it will be firmly 
secured and will not be distorted in any way by im¬ 
perfect clamping. An example is shown in Figure 74, 
where the work is an aluminum casting, A, of more 
or less rectangular shape. 

The V-principle, so-called, in locating work on fix¬ 
tures of various kinds, is based on the fact that a 
piece of work can be put into a Y-shaped block or 
its equivalent in such a way as to act as a locater 
whether the piece is a rough casting or one that has 
previously been machined. It might almost be said 
that the basic principle of jig and fixture design is that 
of locating by means of a form that resembles the 














































FACE-PLATE FIXTURES 


171 


capital letter V—generally written, vee. This vee 
form is often obtained by means of a series of pins 
arranged in proper formation to receive the work. 

In the instance noted in Figure 74, the work, A, 
is placed on the fixture, B, in such a way that it 
locates against the fixed steel pins, C, on one side 
of the fixture and the pin, D, on the other which 
form a sort of vee. The work is forced over against 
the pin, D, in one direction by means of the screw, E; 
while the location in the other direction is performed 
by means of the swinging clamp, F, operated by the 
hollow set-screws, G. It will be seen that the swing¬ 
ing clamps, F, have a knife edge and that the locat¬ 
ing pins at C and D are similarly arranged. The 
purpose of this arrangement is to sink these clamps 
and pins into the surface of the casting slightly, so 
as to keep it from being pulled out while the piece 
is being machined. As the bottom of the casting is 
also rough, it must also be supported, so that the 
work will not be pushed inward toward the face of 
the fixture by the pressure of the cut. This is taken 
care of by means of the spring pins, H, which adapt 
themselves to the rough surface of the casting and 
are firmly locked in position by the set-screws, K, 
in the outer rim of the face-plate. In addition to the 
spring pins, H, the work is given a positive location 
on the fixed pins, N, at three corners of the piece. 

The work which was done upon this casting after 
it was located and clamped, was the facing of the 
surface, L, the turning and sizing of the interrupted 
circular tongue, M, and the boring and reaming of 
the center hole with the reamer, 0. The machine on 


172 


TOOLS AND PATTERNS 



FIG. 75. PLAN AND SECTION OF A FIXTURE WITH SAFEGUARDING 
DEVICES 


which this work was done was a horizontal turret 
lathe, and the equipment for producing the work was 
of a special nature. The principles shown in this 
fixture may be applied to many other examples of 
turret lathe work. 

Fixture for an Irregular Bracket. —The protection 

of workmen engaged in manufacturing is often 
neglected in the design of fixtures for turret lathe 
work and other work that requires similar handling. 
It should be the purpose of every designer to make 
any fixture upon which he is engaged so that it will 
be impossible for a workman to become injured by it. 
It happens occasionally that a piece of work with 
projecting arms or lugs is to be held on a face-plate 
fixture, and when such cases of this kind arise the 
designer should exercise the greatest care to make 
the fixture in such a way that the workman will be 
protected from these projections as they revolve. 

An example of this kind is shown in the piece of 


























FACE-PLATE FIXTURES 


173 


work, A, in Figure 75. This piece has been previously 
machined by milling the surface, B, and cutting the 
tongue, C. It will be seen that the bracket has three 
projecting arms, D, which, if unprotected, might 
strike a workman when machining the piece. The fix¬ 
ture, therefore, is made up with a protecting rim, E, 
of such height that the arms do not extend beyond 
it. The extra cost of making a fixture like this is 
very slight, and in addition to the safety feature, 
the rim, E, also acts as a counterpoise and makes 
the fixture run more smoothly. 

The work is located on the fixture against the fin¬ 
ished pads, D, and the tongue, C, lies in a groove 
provided for it. The work is clamped by means of 
the four straps, F, which are slotted so that they can 
be moved back to allow the work to be set up and 
removed. As in the preceding instance, the body of 
the fixture, G, is screwed to the nose of the spindle, 
as indicated. The work to be done in this case is 
the boring of the hole, H. This work is performed 
by means of the tool, K, mounted on a bar whose 
forward end is piloted by a bushing, L, in the face¬ 
plate fixture. This method of piloting a boring tool 
or other cutting tool assists greatly in producing ac¬ 
curate work, as the bushing acts as a guide for the 
bar and keeps it always in a certain relation to the 

work. . 

Counterbalanced Fixture for a Connecting Rod.— 

For a piece of work that is very much off center 
and is to be bored or otherwise machined at high 
speed, it is often necessary to provide a counter¬ 
balance on the fixture in order to prevent excessive 


174 


TOOLS AND PATTERNS 



FIG. 76. COUNTERBALANCED FACE-PLATE FIXTURE FOR A 
CONNECTING ROD 


vibration from the unevenly balanced rotation of the 
work and fixture. An example is shown in Figure 
76. The fixture here is designed for boring and ream¬ 
ing the hole, A, in the connecting rod, B. The con¬ 
necting rod has been previously drilled and reamed 
at the small end, C, and it is necessary to locate it 
for the remaining operation in such a way that the 
hole, A, will be in a fixed relation to the previously 
reamed hole, C. The face-plate fixture, therefore, is 
made up with a stud on which the portion, C, locates. 
This portion of the work is drawn back against the 
face of the fixture by means of a nut. The large end 
is then correctly located by means of a V-block, D, 
which centers the boss at C. This V-block is under¬ 
cut, as indicated in the sectional view, so that it 
tends to draw the work back against the face of the 
plate, when it is then set up by means of the screw, 
E. This screw is mounted in a swinging latch and 





























FACE-PLATE FIXTURES 


175 


can be thrown back to allow the workman to hook 
his finger into the recess, F, and pnll the block away 
from the work. 

As the fixture is considerably heavier on one side 
than on the other, provision is made for counter¬ 
balancing it by means of the lugs, G. These lugs are 
a part of the cast-iron face-plate and are made heavy 
enough and thick enough to more than balance the 
mechanism on the opposite side of the fixture. 

In balancing a fixture of this kind, the work is 
placed in position and all clamps are set up as if the 
machining was about to be done. The fixture is 
then placed on an arbor and allowed to swing as it 
will. Naturally, the heaviest portion will hang down¬ 
ward. The workman then drills out a portion of 
the stock from the lug, as indicated by the holes, K, 
and tests the fixture again, continuing the operation 
until a proper balance is obtained. Sometimes so 
much stock has been added as a counterbalance that 
it becomes necessary to mill off a portion of the 
counterpoise in order to bring the fixture into 
balance. 

Fixture with Adjustable Counterbalance. —A fix¬ 
ture for turret lathe work or for the engine lathe 
may be needed which will enable several pieces, of 
similar character to be machined upon it by making 
slight modifications. An irregularly-shaped piece of 
work which has a counterbalanced portion, will per¬ 
mit the counterbalance to be shifted radially on the 
plate so that it will balance whatever piece is being 
held upon it. An example of this fixture is shown in 
Figure 77. 


176 


TOOLS AND PATTERNS 



FIG. 77. SECTION AND PLAN OF A FIXTURE WITH ADJUSTABLE 
COUNTERBALANCE 


The work in this case is a worm-gear sector, A, 
which has been previously bored and reamed at B, 
and now is to be machined as indicated at C. The 
work is located on a fixed stud at the center of the 
fixture, and is clamped back against the finished 
pad by means of the nut, E. A “ C-washer,’ ’ F, is 
used with the nut so as to permit the work to be 
removed rapidly. By using such a device it will be 
seen that the nut can be slightly loosened, the C- 
washer slipped out through the slot, and the work 
immediately released without removing the nut, E. 

In order to provide the portion of the work, C, 
with a rigid support, it is swung around against the 
stop pin, H, and is clamped by the screw, K. As 
this side of the fixture, then, is so much heavier 
than the other, it is necessary to provide a counter¬ 
balance at L. This counterbalance is in the form of 
a segmental block with two bolts through it, as indi¬ 
cated at M, which pass through the two slots, and 
































FACE-PLATE FIXTURES 177 

allow the counterbalance to be radially adjusted to 
compensate for pieces of different size. An applica¬ 
tion of this principle of a movable counterbalance 
can be made to many types of lathes, turret lathes, 
and other machines of similar character. In cases 
where the work to be machined is of comparatively 
large diameter, so that the work runs at slow speed, 
it is not usually necessary to counterbalance it. 

Eccentric Fixture for a Ring Pot. —In making up 
packing rings for automobile motors, compressors, 
and the like, an eccentric ring is frequently desir¬ 
able. The ordinary process of machining one of 
these is by means of an eccentric turning device 
which will be described in Chapter XIV. As an 
eccentric device of the character mentioned is some¬ 
what expensive, however, the small manufacturer 
frequently dispenses with such a device and handles 
the work in a slightly different manner. But when 
the device is employed, the work is turned eccen¬ 
trically by means of the device and is also bored 
concentrically at the same time, thus saving a con¬ 
siderable amount of time in the process. 

When an attachment of the kind mentioned is not 
used, it is customary to bore the work in one opera¬ 
tion. The outside eccentric is then turned in an¬ 
other operation, either by means of an eccentric arbor 
or by placing the pot from which the rings are to 
be made on a fixture which can be set eccentrically 
after the hole has been bored. 

In Figure 78, the ring pot, A, is located on the face 
of the fixture by means of the lugs and clamps shown 
at B. The face-plate consists of two parts, one of 


178 


TOOLS AND PATTERNS 



FIG. 78. ECCENTRIC FIXTURE FOR A RING POT 


which, C, is screwed to the end of the spindle, and 
the other, D, is fastened to it by means of the bolts, 
E, which enter slotted holes in the plate, D, to allow 
for a slight movement of the upper plate on the 
lower. The plate, C, is grooved at F, directly across 
its face; and the plate, D, is provided with a tongue 
to slide in this groove. 

In operation, the hole, G, is first bored by a boring 
bar piloted in the bushing, H, in the movable plate. 
After this operation has been done, the nuts at E are 
loosened and the plate is set over the amount indi¬ 
cated by the line at K. The correct distance is de¬ 
termined by pins and bushings at L and M. 

This type of eccentric fixture is very simple and 
answers all purposes for work of this character. It 
is unnecessary to counterbalance the fixture unless 
the eccentricity is so great that the fixture runs out 
of balance when it is set over. 

Swinging Eccentric Fixture.— A fixture may be 
required that will permit a slight amount of adjust¬ 
ment so that it can be set to give two or three eccen- 






























FACE-PLATE FIXTURES 


179 



tricities. In order to provide for a contingency such 
as this it is necessary to make the fixture so that 
the stops which limit the throw of the eccentric are 
adjustable. An example of such a fixture is shown 
at A, Figure 79. The fixture is designed for a hori¬ 
zontal turret lathe for boring and turning eccen¬ 
trically the work, B. The ring pot, B, which is 

to be turned and bored, is held on the plate, C, 

in practically the same way as the pot shown in the 
previous illustration. The mounting of the plate on 
the body of the fixture, however, is arranged in a 
different way. In this case, the plate is pivoted so 

as to swing from the stud, D. The lower portion 

of the body plate, A, is provided with a stop ex¬ 
tending out through a slot in the plate, as indicated 
at B. Adjusting screws, F, on the surface of the 
fixture at E, provide for lateral movement of the 
plate, and suitable clamping bolts, G, on each side 
of the fixture hold it in place. 

When it is desired to set over the work to produce 
the eccentric, the bolts, G, are loosened and the plate 




















180 


TOOLS AND PATTERNS 


swung over until the stud, E, strikes against the set¬ 
screws, F. The amount which these set-screws per¬ 
mit the plate to move, govern the amount of eccen¬ 
tricity. The spacing of the stop, E, is twice the 
distance from the pivot point, D, to the center of 
the work, so that the amount of movement at F is 
exactly twice the eccentricity produced. Fixtures of 
this kind can be used with success on a great variety 
of work, and as they are cheaply made and very 
serviceable they may be considered as excellent types 
of eccentric turning and boring equipment. 


CHAPTER XIII 


ARBORS AND MANDRELS 

Definition of Terms. —The term arbor is applied to 
the cylindrical piece used for mounting cutters upon 
a milling machine. It is also applied to the device 
used to center a piece of work by a previously bored 
or reamed hole so as to bear a distinct relation to 
the hole. The term mandrel is almost synonymous 
with the term arbor as applied to holding work. 
For example, the expressions, “an arbor for a %-inch 
hole,” or “a mandrel for a %-ineh hole,” are used 
interchangeably. The term mandrel, however, is not 
used synonymously with the term arbor when applied 
to the device for holding cutters in a milling ma¬ 
chine. These would always be referred to as “cut¬ 
ter arbors.” 

Arbors are of several kinds—plain arbors, threaded 
arbors, expanding arbors, and cutter arbors. The 
last mentioned is generally used in the milling ma¬ 
chine for holding one or more' cutters in position. 
This type of arbor is quite simple and is variously 
made as a part of the standard equipment for a mill¬ 
ing machine. Such an arbor is shown in Figure 80 
at A. The tang end, B, is tapered to fit the milling 
machine spindle, and may be used in an adapter 
when the spindle taper and that of the arbor do not 


182 


TOOLS AND PATTERNS 



FIG. 80 . ARBOR FOR MILLING MACHINE, ABOVE, AND FOR PLAIN 

LATHE, BELOW 























































































































ARBORS AND MANDRELS 


183 


correspond. The cutters, C, are placed on the arbor 
with one or more spacing collars, D, between them 
to space the distance, E, correctly for the work re¬ 
quired. There is little to he said about milling ma¬ 
chine arbors as their design is so extremely simple. 

A plain arbor or mandrel, indicated at F, Figure 
80, is usually found in the tool crib in all standard 
sizes. It is made up for standard sizes of holes, 
usually with a taper of about 0.006 inch per inch of 
length. When a piece of work, such as that shown 
at G, is to be turned on its surface by the tool, H, 
after it has been reamed in a previous operation, 
it is placed under an arbor press and the arbor, F, 
is forced into it under pressure. As the arbor is 
tapered, it will wedge firmly into the work so that 
there will be no slipping when the pressure of the 
cut is applied. Arbors of this kind are usually de¬ 
signed to be dogged to the face-plate, as indicated in 
the drawing. 

Arbor with Expanding Shoes.— It is often neces¬ 
sary to hold a piece of work that is slightly over or 
under a standard size on an arbor, to perform some 
operation upon the piece which will be absolutely 
concentric with a previously finished hole. Two 
methods of holding are possible. The toolmaker or 
machinist can make up, in comparatively short time, 
such an arbor as that shown in Figure 80, of such 
a size as to suit the hole in the work. Or, if the tool 
crib is well equipped with expanding arbors, it may 
not be necessary to make up a special one for the 
job. 

Expanding arbors are of several types, but perhaps 


184 


TOOLS AND PATTERNS 


the most useful type is that shown in Figure 81. 
Such an arbor can be purchased in various sizes to 
suit any given conditions. The body of the arbor 
is hardened and ground to cylindrical form. It is 
furnished with four slots, A, into which are fitted 
the shoes, B. It will be noticed that the slots are 
cut on a slight longitudinal taper, so that when a 
piece of work is placed on the shoes, they may be 
adjusted along the tapered slots to the required 
diameter. The retaining ring, C, at each end of the 
shoes are slotted to receive the shoes and hold them 
on the arbor when not in use. This type of expand¬ 
ing arbor should form a part of the tool crib equip¬ 
ment and should be bought in a sufficient range of 
sizes to cover the requirements of the class of work 
which is being done. This same type is also largely 
used in general manufacturing, and its adaptability 
suits it for an infinite number of pieces. 

Split Ring Expanding Arbor. —It is sometimes nec¬ 
essary to refinish the outside of a piece of work and 
make sure that it is absolutely concentric with the 
center of the hole that has been previously machined. 
A common type of arbor for this purpose is shown 
in Figure 82 at A. Let it be supposed that the work, 
B, is to be held by the hole previously finished in it, 
and that the work is to done on an engine lathe. A 
steel arbor, C, is then made up with a slight taper 
along its length. A sleeve, D, is split along its length 
at E, and is tapered on the inside so as to fit the 
taper on the arbor, C. When the work, B, is placed 
in position and forced onto the arbor over the split 
ring, the ring expands slightly as it is forced up on 


ARBORS AND MANDRELS 


185 



the taper until it grips the work securely, thus hold¬ 
ing it so that it can be machined readily. This type 
of arbor is not exceptionally good, as it is simply 
split longitudinally. When it opens up, the ring, D, 
therefore, is slightly elliptical and does not expand 
evenly all over. As a cheap arbor that can be used 
for a few pieces, such a device will answer the pur¬ 
pose in many instances, but it should not be used 
for work requiring great accuracy. 

A much better type of arbor, shown at F, can be 
used for work requiring great accuracy. Roughly, 
the principle of the two arbors is the same, except 
that in the instance previously mentioned the ring 
is split in one direction only, while in the example, 
F, the ring, G, is split longitudinally into three slots, 
running from one almost to the other and spaced 120 
degrees apart, as indicated at H. There are also 









































186 


TOOLS AND PATTERNS 


three other slots starting from the other end of the 
ring, spaced equidistantly between the slots men¬ 
tioned, and also running nearly to the end of the 
ring. It will be seen that this arrangement allows 
the ring to be expanded equally all over, making 
a much better construction than that previously 
described. 

An additional requirement on this arbor is seen 
in the nut, K, and washer, L, by means of which 
the ring is forced back on the taper, M, so that it 
expands and holds the work. In the example shown 
at A, it is necessary to use an arbor press to force 
the work on, or else to drive it on with a piece of 
babbitt or wood. For finishing the outside of collars, 
small blanks, and other work of similar character, the 
type of arbor shown at F is very useful, and is fre¬ 
quently found among the tools used for general 
manufacturing. 

Expanding Arbor for an Automobile Flange.— 

Special arbors may be made up to suit a particular 
case when a number of pieces are to be manufac¬ 
tured. One such is shown in Figure 83. In this 
case the work, A, is an automobile flange which has 
been previously bored and reamed at B and C. As 
it is necessary to finish the end, D, and the flange, 

E, the method of holding by the inside surface was 
devised. 

The machine to which this arbor was applied is 
a horizontal turret lathe. The method of holding 
was by means of the collet mechanism with which 
the turret lathe is furnished, the stem of the arbor, 

F, being held as indicated in exactly the same 


ARBORS AND MANDRELS 


187 



FIG. 83 . SECTION THROUGH EXPANDING ARBOR FOR AN 
AUTOMOBILE FLANGE 


manner as that used to hold a piece of bar stock. 
The work then was placed on the portion, G, which 
made a nice tit at this point. After the work was 
so placed, the tapered screw, H, was set up, thus 
expanding or opening up the arbor to grip the points, 
C. A shoulder was also provided on the arbor to 
give longitudinal location at K. 

When making use of the collet mechanism to hold 
an arbor for manufacturing purposes, it is necessary 
to make sure that the collet is perfectly true; other¬ 
wise the arbor might run out of truth and work 
might be produced which would not be concentric. 

An arbor of this kind must be made of tool steel, 
tempered slightly in order that it may expand prop¬ 
erly and come back to place again when the tapered 
screw is released. It will be understood that the 
























































188 


TOOLS AND PATTERNS 


portion of the arbor which is controlled by the ex¬ 
pansion of the tapered screw, is slotted into three 
sections, so that it can be opened np slightly by 
the action of the screw mentioned. 

Expanding Arbor for an Adjusting Nut. Occa¬ 
sionally several pieces of similar character but 
slightly different in size may be machined by the 
same or similar equipment on a turret lathe. An 
example is shown in the pieces A and B, Figure 84. 
These pieces are bronze adjusting nuts in two sizes, 
slightly different both in outside diameter and in the 
location of the spanner holes shown at C. 

Several thousands of these parts were to be made, 
and as it was desirable to make up the equipment 
as cheaply as possible, the arbor was so designed 
that it could be used for both pieces by the aid of 
an adapter. A special nose piece, D, was screwed 
to the end of the spindle, as indicated, shouldered at 
E to receive the ring, F, which was used for the 
piece, A, and also could be fitted with the ring, G, 
for use with the piece, B. In each case the rings 
were provided with pins, H and K. These pins 
entered the spanner holes, as indicated, and assisted 
in driving the work—an essential point in connection 
with an arbor on which any heavy work is to be 
done. The outside of the nut in each case was to 
be threaded with an opening die, so that the pulling 
action of the cut was rather severe. 

A split ring, similar to the one shown at G, Figure 
82, was used to center the work. This ring, of course, 
was very much smaller than the one previously men¬ 
tioned, but the method of splitting was the same. 


ARBORS AND MANDRELS 


189 



FIG. 84 . EXPANDING ARBOR FOR AN ADJUSTING NUT 


In this arbor, it will be observed, expansion was 
procured by means of the tapered plug, L, which 
had a generous bearing, M, in the nose piece. The 
threaded portion, N, was somewhat loose in order 
that the centering action might not be governed by 
the threaded portion, but might be absolutely de¬ 
termined by the cylindrical part, M. The thread was 
simply used'as a means of drawing in on the plug 
and thus expanding the ring at L. 

Applications of this principle may be made to 
many kinds of narrow work when it is necessary to 
do heavy cutting on the outside. It occasionally 
happens that one or more holes are drilled in a piece 
of work in order to provide a means of driving. In 
the particular case mentioned, the spanner holes, 
fortunately, made this unnecessary. 

Expanding Arbor for a Bevel Pinion.— It is par¬ 
ticularly necessary to machine a bevel pinion in such 

























































190 


TOOLS AND PATTERNS 



PIG. 85. SECTION THROUGH EXPANDING SHOE ARBOR FOR A 
BEVEL PINION 


a way that the outside of the gear is in perfect con¬ 
centricity with the hole. In order, therefore, to pro¬ 
vide a means by which such an effect may be secured, 
it is necessary at times to design an arbor of small 
dimensions with adjustable features to provide for 
self-centering. 

Occasionally, also, the kind of tooling which is to 
be used on a piece of this kind has a certain effect 
on the design of the arbor. Such an instance is 
shown in Figure 85. This is an unusual type of 
arbor for it is somewhat delicate in construction. 
Its mechanical features, however, are of considerable 
value, and the principle shown may be applied to 
other work of similar character. 

This arbor was made up for use on a horizontal 
turret lathe in connection with a special taper at¬ 
tachment for generating the angular surface of the 
pinion, A, which had previously been bored and 
reamed on another machine. At the same setting 
of the work, the face, B, was to be machined. Pre- 

















ARBORS AND MANDRELS 


191 


vious to the operation shown and after the hole had 
been reamed, a keyway, C, was cut in the pinion in 
order to provide an efficient means of driving while 
the heavy cutting was taking place at A. The 
spindle of the machine was provided with an adapter, 
D, which had a tapered hole, E, where the stem, F, 
of the arbor was located. A key driver, G, was also 
added to make the driving positively certain. 

As will be seen from the illustration the work 
located on the cylindrical surface, H, which was 
made 0.002 of an inch under the size of the hole in 
the pinion. There are three slots cut in the arbor to 
receive the shoes, K, which were beveled slightly on 
their internal faces so as to fit the taper on the oper¬ 
ating rod, L. This operating rod was pushed back 
into the arbor by means of the screw, M. The por¬ 
tion, N, is ground to fit a shell mill held in the tur¬ 
ret and used for facing the angular surface, B. As 
the operating rod was pushed inward by means of 
the screw, M, the three shoes, K, were forced out¬ 
ward against the inside of the hole in the pinion, 
thus providing an efficient centering action. A sec¬ 
tional view, taken directly across the arbor and 
through the slots, is shown at 0, and a correspond¬ 
ing section of the operating rod is indicated at P. 

Although an arbor of this kind is fairly expensive 
and rather delicate in its construction, it may be 
used in a number of cases where the greatest accu¬ 
racy is necessary. The equipment mentioned is 
really the “last word” in the design of an accurate 
expanding arbor. An additional refinement is found 
in the knurled nut, Q, which is used to start the 


192 


TOOLS AND PATTERNS 


work after it has been machined in the event that 
it might stick slightly. 

Expanding Pin Chuck for a Piston.— Automobile 

pistons, A, Figure 86, and certain other classes of 
work, are made in such form that the inside portion 
is i ‘ cored . 99 A core, if of large size, but not extend¬ 
ing completely through the work, always shows 
a tendency to sag more or less while the casting is 
made, so that the resulting work is not absolutely 
concentric. This is particularly true of automobile 
pistons. Therefore, such work must be held in such 
a way that when it is machined on the outside, the 
surface will be very nearly concentric with the in¬ 
side rough-cored surface, no matter whether the cast¬ 
ing is true when in the rough state or not. 

It is logical to hold such work for the machining 
processes from the inside core, so as to be sure of the 
concentricity. This method of holding makes neces¬ 
sary a rather elaborate arbor. Arbors made for this 
purpose are of various forms, each having some par¬ 
ticular claim for its existence. The example shown 
in Figure 86 is one of the best for this class of work, 
and has been built to suit numerous cases with the 
most satisfactory results. It is by no means a cheap 
arbor, and it requires the greatest care in design 
and the most careful workmanship in machining. Yet 
its action is so satisfactory that in the event of a 
large number of pieces to be machined, the first cost 
of the arbor may almost be neglected. 

The arbor, shown at B, is screwed to the end of 
the spindle, as indicated. It is made of machine 
steel, carbonized, hardened, and ground in its essen- 


ARBORS AND MANDRELS 


193 



FIG. 86. PLAN AND SECTION OF EXPANDING PIN CHUCK FOR A 
PISTON 


tial parts. Six pins are so spaced as to be equi¬ 
distant around the periphery at C, while at D they 
are arranged in such a way as not to interfere with 
the wrist pin bosses shown in the upper sectional 
view at E. The lower ends of the pins are beveled 
to ride on the two cams, F and G. These cams are 
threaded right and left hand to tit the screw, 11, 
which is provided with a slot, K, for operating pur¬ 
poses_a pair of bevel pinions, at L and M, being 

used as the operating means. It will be seen that 
when the pinion, L, is revolved by means of a special 
socket wrench, the motion is transferred to the 












































































194 


TOOLS AND PATTERNS 


pinion, M, which turns the threaded shaft, H, and 
causes the cams, F and G, to approach or recede 
from each other according to the direction of rota¬ 
tion. 

A valuable point in connection with this piece 
of mechanism is the fact that the pressure exerted 
on the pins C and D is equalized, so that the amount 
of force exerted on all six pins is the same. This 
equalizing action is caused by the ‘‘float ’’ in the two 
cams. As the shaft, H, is free to move slightly 
longitudinally, the pressure is distributed on the 
two cams in an equal ratio. The cams are prevented 
from turning by means of the set-screws, 0. 

Threaded and Knock-off Arbors. —Tapping out a 
piece of work in such a way that the threaded por¬ 
tion will be in perfect concentricity with the out¬ 
side and with the ends of the work, is a difficult oper¬ 
ation. It is, therefore, necessary to provide some 
means of re-finishing the outside of the work or the 
ends, using the threaded portion as a locating point. 
The simplest type of arbor which can be devised for 
holding a piece of threaded work is that shown at A, 
Figure 87. In this arbor a portion, B, is threaded 
to receive the work, which is screwed upon it and 
makes up against the shoulder, D. 

This arbor is held on centers in an engine lathe 
and is driven by means of a dog in the usual man¬ 
ner. While it will give satisfactory results, it is 
by no means a convenient type to use, for the reason 
that the pressure of the cut in finishing the outside 
of the work is such that it causes the piece to 
“ freeze’* up against the shoulder, D, so that it is 


ARBORS AND MANDRELS 


195 



difficult to remove it without the use of a pipe wrench 
or special clamps. 

A much better type of arbor and one which over¬ 
comes this trouble, is shown at E in the lower illus¬ 
tration. This arbor is threaded in the same manner 
as the upper one in Figure 87, except that the work, 
F, does not make up against the shoulder, G, but 
rather against the flange, H. This flange, however, 
fits against a shoulder, K, on the arbor, so that the 
longitudinal location of the work always comes the 

Same * . ,, 
Provision for removing the work without difhculty 

is as follows: The arbor is threaded, at L, with a 






































































196 


TOOLS AND PATTERNS 


coarse left-hand thread on which the flange, H, is 
screwed until it strikes against the shoulder, K. The 
flange is provided with two lugs, M, on opposite sides 
in order to make the matter of releasing easy. When 
the work has been finished, it is only necessary to 
strike either of these lugs a sharp blow with a bab¬ 
bitt hammer or piece of wood and the work is at 
once released, because the end of the work is backed 
away from the flange, H. It is an easy matter, then, 
to release the piece from the arbor without the aid 
of any tools except the workman’s hands. 

Knock-off Arbor for Threaded Collars.—An excel¬ 
lent example of a knock-off arbor designed for 
handling a number of pieces of threaded work of 
different sized threads and pitches is shown in Figure 
88. There were a number of collars such as those 
shown at A, B, and C; the manufacturing require¬ 
ments of which made it necessary to have the ends 
square with the thread. An equipment was designed, 
therefore, so that by means of adapters, such as those 
shown at D, E, and F, and with threaded arbors 
as that shown at G, a number of different sizes could 
be handled with little trouble. A master bushing, 
H, was inserted in the spindle of a turret lathe, as 
indicated. In it the adapters, G, were located by 
means of the taper at K, and were drawn by a bolt, 
L, provided with a spherical washer, M, in order to 
equalize any strain caused by the action of the bolts 
in drawing the work back into the taper, K. The 
master bushing was provided with a threaded por¬ 
tion, N, and a shoulder, 0, against which a plate, P, 
gave the correct location to the work. The threaded 


ARBORS AND MANDRELS 


197 



FIG. 88. KNOCK-OFF ARBOR FOR THREADED COLLARS 


portion was made left hand, as in the preceding 
instance. A knock-off flange, Q, was made with a 
finished pad, K, so that a spacing collar, F, could 
be used in connection with the work. 

In operation, the threaded flange is screwed up 
until it makes against the shoulder at O; the spacer, 
F, is inserted, and the work, C, is screwed onto the 
arbor. Then, after the machining has been done, 
the lugs, S, are given a sharp blow with the hammer 
or a block of wood, and the work is immediately 







































































































198 


TOOLS AND PATTERNS 


released so that it can be removed from the arbor. 
I made up an equipment of this kind to handle 
twelve pieces of different diameters and different 
threads, and its operation was very satisfactory. 
Moreoyer, the same principle may be applied in many 
other cases where threaded work is to be machined. 

Special Arbor for an Eccentric Packing Ring.— 
The packing ring, shown at A, Figure 89, is a type 
commonly used for compressors and automobile 
motors. The operations on a ring of this kind are 
as follows: A pot casting is first made up and held 
in such a way that it can be turned eccentrically 
and bored at the same time. In the same operation 
the rings are cut off from %-inch to %-inch wide. 
After they have been cut off they are ground to the 
correct thickness, and are then cut with a diagonal 
cut, as indicated at B, and from 5/32 to 3/16 of an 
inch of metal is taken off of each. 

When one of these rings is closed up so that the 
edges at B are in contact, it will be found that the 
ring is slightly elliptical. To counteract this ellipse 
and to make the ring true once more, it must be 
turned or ground on the outside. A special arbor 
of an unusual type is used for this purpose, the con¬ 
struction being practically the same whether it is 
used for turning or grinding. The arbor, C, is ar¬ 
ranged so that it can be dogged at one end and held 
on centers in an engine lathe or on a cylindrical 
grinder. A locating flange, D, and a sliding sleeve, 
E, fit snugly on the portion, C. 

The particular type of arbor shown in this illus¬ 
tration is intended to take two packing rings, F. 


ARBORS AND MANDRELS 


199 



FIG. 89 . SPECIAL ARBOR FOR AN ECCENTRIC PACKING RING 


These are held firmly against the shoulder by means 
of the threaded piece, G, which is hexagonal so that 
a wrench can be used upon it. In using this arbor, 
the hexagonal nut, H, is removed and the rings, F, 
are set into the sleeve; the threaded nut is then 
screwed up upon them until they are firmly held 
against the shoulders at D. The sliding sleeve is 
now pulled hack out of the way,, until the detent 
pin, K, snaps into the groove, L, which keeps it out 
of the way of the tool while the work is being done. 
An air hole is provided at M, in order to relieve the 
suction and allow the sleeve to be pushed back 
away from the work without difficulty. Were it not 
for this provision it would be practically impossible 
to pull back the sleeve. 

Arbors of this kind are in very common use in 
automobile factories throughout the country. Prac¬ 
tically all are made on the same general style, al¬ 
though refinements are sometimes found tending 
toward more rapid manipulation and quicker hand¬ 
ling. However, the type shown is an excellent ex¬ 
ample of an arbor for work of this character. 




















CHAPTER XIV 


GENERATING AND FORMING ATTACHMENTS 

Generating Curved Surfaces. —A cylindrical piece 
of work may be formed to a prescribed shape by 
means of a tool itself shaped to the correct contour, 
or the shape may be generated by a single tool used 
with a special attachment on an engine lathe, a turret 
lathe, or a vertical boring mill. If the work to be 
formed is not cylindrical, a suitable forming attach¬ 
ment can be applied either to a planer, a shaper, 
or a milling machine in such a way as to produce 
the desired shape, either with a cutter of special 
form or with a forming plate that controls the move¬ 
ment of the cutting tool. 

Attachments for the planer, shaper, and milling 
machine are rarely used, except on special work, and as 
they are highly specialized and the design is gen¬ 
erally developed to suit the particular pieces to be 
machined, it is not necessary to describe them here. 

For some very large work, a radial attachment 
can be applied to a planer and used to generate a 
curved surface. It is also possible to apply a taper 
attachment to a planer, but this is not usual as the 
work can frequently be set at such an angle that the 
tapered surface to be machined will be in the same 
plane as the top of the table. Special forms can be 
200 


GENERATING AND FORMING ATTACHMENTS 201 


machined on a planer by means of a forming attach¬ 
ment which controls the movement of the tool on the 
rail. In milling machine work it is seldom that an 
attachment to produce contours is required. The 
form of the piece to he milled can be easily generated 
on a profiler by suitable forming plates. It is en¬ 
tirely possible, however, to generate simple forms on 
a milling machine by the application of a proper 
fixture and a suitable forming plate. These several 
machines are so seldom used for forming that we 
have only the proposition of forming as applied, to 
the engine lathe, turret lathe, and vertical boring 
mill to consider. Therefore, as these three machines 
are most commonly used for work of a cylindrical 
nature, the attachments described are particularly 
applicable to this class. 

Simple Radius Generating Attachment.— The en¬ 
gine lathe is frequently used either by the applica¬ 
tion of a forming attachment at the back of the lathe 
or by some special arrangement applied in a suitable 
manner. The construction of any such attachment 
depends somewhat upon the work to be machined. 
Standard forming attachments applied to the rear 
of the machine can be obtained from manufacturers 
of certain engine lathes; but as these attachments 
are generally designed to operate longitudinally along 
the work, other arrangements are necessary when it 
is desired to generate a form on the end of a cylindrical 
piece. 

An example of the latter is shown in Figure 90, 
where an arrangement for generating a radius on 
the end of the piston is seen at A. It will be noticed 


202 


TOOLS AND PATTERNS 



FIG. 90 . RADIUS GENERATING ATTACHMENT FOR AN ENGINE LATHE 


that the end of the work is formed to a perfect 
radius, and also that the surface is so large that it 
could not properly be formed with a single tool. The 
application of the attachment to the lathe made it 
possible to generate the radius shown in a short 
time; furthermore the attachment itself was compar- 































































































GENERATING AND FORMING ATTACHMENTS 203 

atively inexpensive. The design was such that con¬ 
siderable flexibility was possible, both in the length 
of the radius and in its position with relation to the 
center of the spindle. 

The construction of the attachment is simple; a 
special block, B, is supplied with a swivel top, C, 
the upper part of which was dovetailed at D. The 
tool-block, L, was furnished with a tool, E, for cut¬ 
ting the correct form. A special form of bracket, F, 
is fastened to the carriage as indicated, and a T-slot, 
G, is cut in it to provide for transverse adjustment 
of the pivot, H. The arm, K, swings on this pivot, 
and is attached to the tool-block, L. Thus it will 
be seen that as the cross feed of the carriage is 
operated, the tool, E, will be constrained to follow 
the path indicated by the dotted line, M; except that 
it can be moved radially as permitted in the tool- 
block so as to obtain radii of different lengths, if 
desired, and also to compensate for re-grinding the 
tool when it becomes worn. 

The attachment shown was designed by me a num¬ 
ber of years ago for an automobile plant in Massa¬ 
chusetts, and since that time I have used the same 
idea in several other cases to good advantage. The 
principal value of this attachment is that it can be 
made up so cheaply. In addition, it does the work 
required of it with practically no attention on the 
part of the operator, and the results produced give 
excellent satisfaction. 

Radius Forming Attachment for Crowning Pul¬ 
leys. —The ordinary cast-iron pulley, so largely used 
in machine work, has a ‘ 4 crown” or radius on the 


204 


TOOLS AND PATTERNS 


face to which the belt is applied, the purpose of 
which is to keep the belt from running oft. The 
metal in the pulley at the point which is crowned 
is usually thin, and consequently cannot be formed 
with a wide tool of the proper shape to good advan¬ 
tage. In machining these surfaces it is therefore 
necessary to generate the form by means of a form¬ 
ing attachment. 

In the instance shown in Figure 91, the attachment 
was so made that two pulleys could be crowned at 
the same time with the two tools indicated at A in 
the upper part of the illustration. The work, B, 
shown in the lower part of the figure, is held on an 
arbor, C, and driven by means of the driver, D, ex¬ 
tending through the face-plate and between the 
spokes of the pulleys, as indicated. This attachment 
was applied to an old-style lathe, and the necessary 
movement was imparted to the tool-block, E, by 
means of the rod, F, passing completely through to 
the back of the lathe as shown. A roller, G, made 
contact with the forming plate, H, and was held in 
place by means of the spring, K. The bracket, L, 
was fastened to the back of the lathe carriage and 
was simply used to form a thrust surface for the 
spring. It will be seen that as the carriage is trav¬ 
ersed longitudinally, the two tools will follow the 
form indicated at H, thus generating the desired 
surface. 

If an engine lathe is furnished with a forming 
attachment, work of the character shown in Figure 
91 can be more easily handled by the application 
of a suitable forming plate to the forming slide at 


GENERATING AND FORMING ATTACHMENTS 205 



FIG. 91. PLAN AND ELEVATION OF A RADIUS-FORMING ATTACH¬ 
MENT FOR CROWNING PULLEYS 


the rear of the machine. But the general construc¬ 
tion of attachments of this kind is similar to the 
one shown. Many varieties of forms can be generated 
by means of forming attachments on the engine 


























































































206 


TOOLS AND PATTERNS 


lathe; it is only necessary to provide a plate to suit 
any given case. 

Piston Forming and Grooving Attachment. —As 

automobile pistons are produced in large lots, every 
effort is made to design the various tools used in 
the manufacture, so as to provide maximum produc¬ 
tion. And as the piston of an automobile is a vital 
part of the motor, the greatest care is used in the 
manufacture to insure uniformity and accuracy. 

Turret lathes are largely used for work of this 
character, and attachments are frequently applied for 
combining several operations in one. An excellent 
example of a forming attachment which is combined 
with two equipments for grooving the piston, is 
shown in Figure 92. A plan view looking down upon 
the machine is shown in order to make the manner 
of operation more apparent. 

The turret of the machine is used simultaneously 
with the tool shown in the plan view, but as the 
turret tools have nothing to do with the forming 
attachment, it would be confusing to show them here. 
The piston in this case is held on a special chuck, 
A, this chuck being somewhat similar to that de¬ 
scribed in Chapter XIII, Figure 86. The work to 
be done is the forming of the ends of the piston, B, 
to the required radius, and simultaneously to make 
the annular grooves, C and D. 

In the first place, the cross-slide is furnished with 
a special block, dovetailed to receive the sliding 
member which is carried under the block that holds 
the grooving tool for the surfaces C and D. The 
dovetailed slide, E, has a roller at F, which is guided 


GENERATING AND FORMING ATTACHMENTS 207 



be seen that as the cross-slide feed is engaged, the 
tool for turning the ends of the piston at B travels 
across the lathe carriage in the path directed by the 
forming plates. At the same time, the grooving tools 
are slowly moving forward, until they reach the 
outside of the piston and begin to cut. At this time 
the operator changes the feed to a very slow one, so 
that the grooving tools cut only a little at a time 
and do not have any tendency to chatter. The feed 
for a cut of this kind on any kind of a job must be slow, 
to produce good results, as the cutting action of a 
grooving tool is not very good. 





































































208 


TOOLS AND PATTERNS 


It is obvious that any sucb equipment as the one 
described herewith would only be warranted when 
high production is desired. Attachments of this 
kind, however, are applicable to many varieties of 
work, and combinations of tools can be made to cover 
many different cases. The number of pieces to be 
machined must always be considered when designing 
any sort of special equipment, in order that the ex¬ 
pense may be proportional to the production. 

Angular Generating Cross-Slide. —For finishing the 
faces on large ring gears, the angular cut across the 
face of the gear usually requires a special forming 
attachment or special equipment of some character. 
It is entirely possible to machine work of this kind 
by means of a forming attachment similar to the one 
indicated in Figure 92, but, of course, it would be 
necessary to make the forming plates to the correct, 
angle of the bevel on the face of the gear. 

A more convenient attachment for either an engine 
lathe or a turret lathe can be made up, as shown in 
Figure 93. This is a special swivel cross-slide, and 
is designed to take the place of the regular cross¬ 
slide on the machine, which must be removed to 
allow the swivel slide to be put in position. The 
particular advantage of a cross-slide of this char- 
cater is that it can be swung radially about the cen¬ 
ter, A, to any angle within its capacity. The ring 
gear, shown at B in this instance, is to be machined 
along the face, C. The tool-block, D, on the swivel 
cross-slide is furnished with two tools, as indicated, 
for roughing and finishing this angular plate, which 
are set far enough apart so that the roughing tool 


GENERATING AND FORMING ATTACHMENTS 209 



FIG. 93. SPECIAL SWIVEL CROSS-SLIDE FOR A TURRET LATHE 


completes its work before the finishing tool starts 
on the face of the gear. 

A swivel cross-slide is not by any means a cheap 
attachment, but its usefulness and flexibility is such 
that it can be used advantageously on many kinds 
of work requiring an angular generating device. 
Even though the attachment is rather expensive, 
the construction is simple and it is not likely to get 
out of order. The feed screw which operates the 
slide is controlled by a pair of bevel pinions at the 
center which are always in mesh no matter what the 
angle of the slide may be. A suitable knock-off can 
be easily provided to stop the cutting action at any 
desired point. 

Eccentric Turning Device for Packing Rings — 

Packing rings for automobile motors are frequently 














































210 


TOOLS AND PATTERNS 



FIG. 94. ECCENTRIC TURNING DEVICE FOR PACKING RINGS 


made eccentric, and it is a decided advantage to be 
able to bore the inside of the ring and turn it eccen¬ 
tric at the same time. For this purpose, several 
manufacturers of turret lathes have developed equip¬ 
ment to apply to their own product. One such is 
shown in Figure 94—the eccentric turning and bor¬ 
ing attachment for a turret lathe, manufactured and 
patented by Pratt & Whitney Co. 

The work, A, in the drawing, is held by chuck 
jaws, B, in a three-jawed gear scroll chuck, the face¬ 
plate of which forms a ring gear at C, and drives 
another gear of equal size, D. The latter gear is 
mounted on a shaft, splined at E, and carried by a 


















































































GENERATING AND FORMING ATTACHMENTS 211 

bracket, F, on the spindle cap of the machine. A 
supplementary bracket, G, is mounted on the turret 
and carries a slide, H, in which the tool, K, is 
mounted. This tool is used for turning the outside 
of the casting, A, eccentric to the inside. The slide, 
H, is held by the pressure of a stiff spring against a 
cam, shown at L. As the work revolves, the shaft 
on which the cam, L, is mounted revolves at exactly 
the same speed. And as the cam revolves, it bears 
against a small roller, M, mounted in the slide, so 
that it moves the tool, K, continually in and out to 
form an eccentric on the outside of the work. Simul¬ 
taneously with the turning of the outside of the pot, 
a boring bar, N, having a tool, 0, is used to bore the 
inside of the ring. Coincident with the action of the 
boring and turning tool, the tool-block, P, moves 
transversely, so that the gang of tools mounted on it 
cut off the packing rings one by one. 

This is an excellent example of the application of 
special attachments to a turret lathe, and indicates 
the possibilities of this class of machine in manu¬ 
facturing processes. 

Bevel Generating Attachment for a Turret Lathe.— 

The possibilities of the horizontal turret lathe are 
little appreciated by the average manufacturer, and 
it is remarkable how poor a showing some of these 
high-capacity machines are making in many factories 
simply because tool designers are not as bold in de¬ 
signs as they might be. For bevel pinions, and other 
angular work of similar character in which the angle 
is less than 40 degrees on one side of the center line 
of the work, a generating attachment for a hori- 


212 


TOOLS AND PATTERNS 



FIG. 95. BEVEL GENERATING ATTACHMENT FOR A TURRET LATHE 


zontal turret lathe may be made that will handle a 
wide variety of work. Such an attachment is shown 
in Figure 95. The work, A, is held on a special form 
of arbor where the pilot, B, enters a bushing, C, in 
the face of the attachment and makes the probabil¬ 
ity of chatter very remote. The turret of the ma¬ 
chine is furnished with a bracket fastened against 
one of the turret faces, as shown at D. This extends 
out and overhangs the turret and has a steel pilot, 

E, at its forward end, which is guided in a bushing, 

F, supported by the bracket, G. This bracket in turn 
is fastened to the spindle cap, or to some part of the 
head construction which is sufficiently massive to 
permit its being used as a support. This portion of 
the design depends largely upon the type of turret 
lathe to which it is to be applied. 

The bracket, B, that is fastened to the turret face, 


















































GENERATING AND FORMING ATTACHMENTS 213 

is furnished with a special slide, H, to which tool- 
blocks, such as that shown at K, can he readily ap¬ 
plied. These tool-blocks may have one or more tools 
in them according to the work for which they are 
intended. The slide itself is free to move up and 
down as held by the straps, L. The back of the slide 
is furnished with a block, M, that is free to swivel. 
A powerful spring, adjusted by means of the screw 
shown at M, holds the entire slide up until the sv ivel 
block strikes the bevel indicated at 0. This bevel 
is cut on a long rectangular bar of steel, P, properly 
fitted to a slot in the fixture. The angle of the bevel 
is made according to the work to be done, but any 
number of bars may be made up for different bevels, 
and they can be replaced and substituted one for the 
other in a moment’s time. 

The action of this device is extremely satisfactory, 
and its adaptability is such that it can be applied 
to a wide variety of work. In operation, the end 
of the tapered bar (which is guided in the bracket 
on the headstock) comes against a stop (not shown) 
before the cutting action of the tool, Q, commences. 
As the tapered bar does not move after it has been 
brought to the stop, it is obvious that the entire 
taper-turning device moves forward along the taper 
bar, and that the swivel block, M, follows the angle, 
0 on the tapered bar as it is constrained to do by 
the swing at the back of the slide. The tool, there¬ 
fore, follows the same angle, and generates the cor- 
rect taper on the work. 

After the work has been finished, the entire mech- 
anism is withdrawn by a backward movement of the 


214 


TOOLS AND PATTERNS 


turret, and any other tools which are on the turret 
in other positions can be brought into action. After 
the work has been done on one piece, another one is 
put in position on the arbor, and the turret is in¬ 
dexed to its original position. After this has been 
done, the lever, R, is pulled forward to throw the 
tapered bar ahead into its original position ready 
for the new job of work. 

An equipment of this kind may be made up with 
two attachments, one of which can be used for rough¬ 
ing and the other for finishing. These two attach¬ 
ments can be on opposite sides of the turret and may 
be tied together by means of a suitable tie-bracket, 
such as that shown at S. I have designed several 
equipments of this kind for bevel gear work and 
other angular work, and have found them very satis¬ 
factory in action. 

Radius Generating Attachment for a Vertical Turret 
Lathe. —The Bullard vertical turret lathe is adaptable 
in many ways: By the aid of forming attachments 
almost any kind of shape may be generated, and the 
machine is of such rigidity that the heaviest cut can 
be taken with impunity. Incidentally, in regard to 
the power of the machine, the story is told that upon 
being asked by a prospective customer, “How many 
machines can be handled by one man,” Mr. Bullard 
replied, “It takes two men to operate one machine, 
one to handle the machine and the other to carry 
away the chips.’’ 

The simple attachment for this type of machine, 
shown in Figure 96, is for forming or generating 
a radius on the surface of the large pulley, A. The 


GENERATING AND FORMING ATTACHMENTS 215 



PIG. 96. RADIUS GENERATING ATTACHMENT POR PACING A PULUEY 
ON THE BULLARD VERTICAL TURRET LATHE 


forming or generating is accomplished by means of 
the side head with the tool shown at B, and attach¬ 
ments, consisting of a couple of brackets, C and D, 
are attached to the column of the machine. These 
brackets support a slotted plate, B, by means of the 
bars, F and G, which are adjustable vertically. The 
side head is provided with a T-slot, H, in which a 
link is pivoted, as shown at K. The radius of the 
link determines the radius to he generated by the 
tool at B, and as the link is of the very simplest 
construction it will be seen that different radii can 
















































216 


TOOLS AND PATTERNS 


be readily established by simply providing an extra 
link of the desired length. The plate, E, being 
slotted at L, allows the link to be fastened at any 
desired point in the slot, so as to determine the exact 
center from which the radius is to be described. 
There is little cost connected with the manufacture of 
an attachment of this kind, and its usefulness and 
adaptability is quite evident. 

Angular Generating Attachment for Vertical Tur¬ 
ret Lathe. —To machine an angular surface, such as 
that shown at A, Figure 97, on work of large size, 
a Bullard vertical turret lathe may be supplied with 
an angular generating attachment. Let it be sup¬ 
posed that the bevel ring gear shown is to be ma¬ 
chined along the surface, A, with an attachment 
such as that indicated in the illustration. The tool, 
B, in this case is held in the turret of the side head, 
and angular motion is obtained by means of the 
roller, D, which bears against the angular plate, C. 
The angular plate is fastened to the side-head ram 
and is adjustable along the T-slot, X. The roller, D, 
is also adjustable up or down in the slot shown in 
the vertical plate, E. Provision for quick removal 
of the roller is made in the large holes at each end 
of the slot. The slotted plate is supported in much 
the same manner as that shown in Figure 96. By 
means of a forming plate in place of the angular 
plate, this attachment may be used for forming differ¬ 
ent shapes if desired, and the entire attachment is 
sufficiently flexible to handle work with quite wide 
variations. When ,the vertical turret lathe is used 
for heavy manufacturing in quantities, an attachment 


GENERATING AND FORMING ATTACHMENTS 217 



of this kind may be applied with excellent results. 

Internal Radius Boring Attachment.— It is occa¬ 
sionally necessary to machine an inside radius on a 
piece of work, and although conditions requiring 
such an operation are rather rare, “it is the unex¬ 
pected that always happens.” 





































































218 


TOOLS AND PATTERNS 



FIG. 98. INTERNAL-RADIUS BORING ATTACHMENT 


Let us assume, then, that the work shown, A, 
Figure 98, is to be machined to the shape indicated, 
and that the work is to be done on a vertical turret 
lathe. The attachment shown, made up for the work 
of the nature indicated several years ago with ex¬ 
cellent results, is entirely self-contained in the bar, B. 
This bar is located in the turret of the machine and 
is of massive proportions so that it may be rigid 
enough for the work. The bar is slotted to receive 
a swiveled toolholder, carrying at each end the tools, 













































GENERATING AND FORMING ATTACHMENTS 219 

C and D, set to cut the same radius from the center 
of the bar. A link motion allows the lug at the end, 
E, to travel radially when it is pushed downward 
by the sliding block, F, operated by a special rec¬ 
tangular piece, G, in the side-head turret of the ma¬ 
chine. It will be seen that when the side-head down- 
feed is started, the action of the sliding block causes 
the cutting tools, C and D, to describe an arc, thus 
generating the inside radius. Rigidity of the bar is 
assured by the pilot, H, which enters a bushing in 
the center of the table as indicated. 

This attachment is decidedly special, and was con¬ 
structed for a particular piece of work requiring con¬ 
siderable accuracy. It is not to be supposed that 
such an equipment will be frequently called for, but 
conditions may arise in any factory which may neces¬ 
sitate some arrangement for internal radius boring, 
in which event an equipment of this kind would be 
of the greatest use. 


CHAPTER XV 


VERTICAL BORING MILL FIXTURES 

Fundamental Construction Features. —Fixtures de¬ 
signed for vertical boring mills are naturally much 
heavier in construction than those used on a hori¬ 
zontal turret lathe or on the engine lathe. This is 
perfectly logical, because the work done on a ver¬ 
tical boring mill requires heavier speeds and feeds 
than the class of work done on the smaller and 
lighter machines. While a vertical boring mill, or 
a vertical turret lathe equipped with a side-head, is 
used for machining many of the same styles of 
pieces as those handled on a horizontal turret lathe, 
the difference in the work, however, is one of size; 
there is comparatively no difference in the method 
of holding. 

One thing, however, must be mentioned in connec¬ 
tion with work on the vertical boring mill. That is 
that the work is revolved in a horizontal plane, and 
it is not necessary, therefore, to counterbalance any 
fixture made for an odd-shaped piece, as it would be 
if the work were to be done on a horizontal ma¬ 
chine, where the work revolves in a vertical plane. 
That is to say, the work spindle on a vertical boring 
mill has the center line or axis of rotation in a ver¬ 
tical plane, and the work revolves horizontally; 

220 


VERTICAL BORING MILL FIXTURES 


221 


while on the horizontal turret lathe the center line 
or axis of rotation is in a horizontal plane, and the 
work revolves vertically. 

In vertical boring mill practice, therefore, the 
work may be laid down on the table of the machine 
and can readily be clamped down to it. The weight 
of the piece really assists in holding it; and the only 
thing necessary in the clamping device is that pres¬ 
sure enough be applied to keep the work from slip¬ 
ping under the pressure of the cut. It must also 
be remembered that the cuts taken on these heavy 
boring mills, are greatly in excess of those used on 
horizontal machines. 

For many kinds of heavy manufacturing work the 
vertical boring mill or vertical turret lathe can be 
used to great advantage, and the massive construc¬ 
tion of these machines permits work to be done 
within close limits of accuracy. Furthermore, ma¬ 
chines of this type can be easily set up with a com¬ 
paratively small outlay for tool equipment, so that 
although the first cost of the machines is rather large, 
the productive efficiency is extremely high. 

Vertical Boring Mill Fixture for Thin Work.— 
The problem of holding and machining a piece of 
thin work is always more or less difficult, because 
it is not easy to hold the work without distorting it, 
and in addition, the work is likely to be sprung out 
of shape by the pressure of the cut in machining. 
It is necessary, therefore, in designing a method 
for holding a piece of thin work, to strive to prevent 
both distortion from the holding device and distor¬ 
tion from the pressure of the cutting tool. 


222 


TOOLS AND PATTERNS 



PIG. 99 . METHOD OF HOLDING THIN WORK ON A VERTICAL 

BORING MILL 





















































VERTICAL BORING MILL FIXTURES 223 

An excellent example of a piece of work of thin 
section to be machined on the vertical boring mill 
is shown in Figure 99. The method used for hold¬ 
ing this piece and supporting it while machining, 
can be applied to a number of cases of similar char¬ 
acter with slight variations. The work is large in 
diameter, and it is necessary to machine it on the 
surfaces A, B, C, and D. Since the web, B, is very 
thin, it is necessary to support this portion of the 
work to keep it from swinging downward while the 
cutting tool is in action. The direction of the cut 
is indicated by the arrows; and the tool which is 
used on the portions B and C, is shown at E in the 
side-head of the machine. The work is laid down 
upon a special cast-iron locating ring, F, which is 
held down by lugs, indicated at G, in the table key- 
slots. The work is centered by means of the special 
hook-bolt jaws, H, which are soft and bored out to 
fit the outside of the work. (Incidentally, the work 
has been finished on the surface, K, in a previous 
setting.) The three jaws indicated are attached to 
the master jaws on the table chuck, as shown in the 
upper view, and, as the table chuck is of the three- 
jawed geared scroll variety, the work is readily cen¬ 
tered on the table. The jaws are brought up very 
lightly on the outside of the work, so as not to cause 
any distortion; and after they are brought in con¬ 
tact with the work, the hook bolts, L, are tightened 
by means of the nut, M, so that the work is gripped 
at three points around the circumference in much 
the same manner as though it were held in three 
separate vises. It can be easily seen that this method 


224 


TOOLS AND PATTERNS 


of holding is exceptionally rigid and does not cause 
distortion in the work. The pot, F, acts as a locat¬ 
ing device to give the correct height to the work, 
and at the same time it supports it against the 
pressure of the cut. 

Special Fixture with Tapered Plug Locater. —It is 

frequently necessary to locate a piece of work on a 
tapered hole that has previously been machined, and 
at the same time to hold the piece by means of 
clamps on some other portion. As it is a difficult 
matter to machine a tapered surface and a plane sur¬ 
face so that they will always bear an exact relation 
to each other, some method of holding must be used 
which will compensate for the variations between 
the two surfaces. 

Let us take as an example of this kind of work 
the piece shown at A, Figure 100. This work is a 
flywheel for an automobile engine, and it has been 
machined in a previous setting in the tapered hole, B, 
and also on surfaces C, D, and E. Now in order to 
machine the side of the work, F, and the hub, G, 
so that they will be in the correct relation to the 
previously machined tapered hole, it is necessary to 
locate the work on a plug in this tapered hole. But 
while this location would be all right, it would not 
be possible to clamp the work easily without spring¬ 
ing it out of shape if it were to be located only on 
the tapered plug. The surface, D, then, must be 
used for attaching an additional clamp, but as this 
surface may vary slightly in its relation to the 
tapered hole, any method of clamping must be so 
designed that compensation may be made for sur- 


VERTICAL BORING MILL FIXTURES 


225 



FIG. 100. HOLDING A PIECE OF WORK BY ITS TAPERED HOLE 


face variations. This is accomplished by making 
a tapered plug or shell, as shown at H, and locating 
this shell on a threaded stud, K, set in the center 
hole in the table. The upper end of the tapered 
shell is squared out to receive the special socket 
wrench, L, by means of which it is operated. 






















































226 


TOOLS AND PATTERNS 


The method of using this fixture is as follows: 
The plug is lowered by means of the screw, so that 
the work can slip onto it loosely. The clamps, M, 
which are three in number, are then set up lightly 
on the rim, C. After this, the socket wrench, L, is 
used to screw the tapered bushing up in the hole, 
thus locating the work on the tapered portion. After 
this has been done the clamps are tightened securely, 
and the work is ready for machining. 

Applications of this principle can often be used 
to hold work of this character, with various methods 
of compensating. The tapered shell bushing is some¬ 
times arranged on a spring, so that it is self-locat¬ 
ing. A method of this kind is quite satisfactory and 
generally gives good results. 

Expanding Arbor and Faceplate for Vertical Bor¬ 
ing Mill. —For a piece of work that has been pre¬ 
viously machined and is to be located in the second 
setting by the previously machined surface, it is 
necessary to make up a locating fixture. A good 
example of such a fixture is shown in Figure 101. 
In this case the work, which is a double bevel gear, 
has been previously machined at A and B, and on 
the bevel-gear faces, C and D. It is necessary to 
locate it for this operation by means of the hole, B, 
and, as the work must be very accurately done, an 
expanding arbor must be used in the hole. In con¬ 
junction with the expanding arbor, it is necessary to 
prevent the work from springing at the surfaces of 
the outer bevel-gear ring, D. 

A cast-iron fixture body, E, is located in the center 
of the table by means of the plug, F, which enters 


VERTICAL BORING MILL FIXTURES 


227 



PIG. 101 . PLAN AND SECTION OP EXPANDING ARBOR AND PACE 
PLATE FOR VERTICAL BORING MILL 

















































































228 


TOOLS AND PATTERNS 


the center hole. The work is placed in position 
over the central ping and drops down against the 
surface, A, of the fixture. A split ring, G, similar 
to the type described under the heading “ Split Ring 
Expanding Arbor/’ Chapter XIII, is then expanded 
by means of the bolt, H, thus giving the desired 
centering action. The spring jacks, K, are now re¬ 
leased and allowed to spring up against the surface, 
D, after which they are locked by means of the set¬ 
screws, L. The final clamping of the work is ac¬ 
complished by means of the hook-bolts, M, which are 
operated by the bolts, N. 

The principle shown in this fixture can be applied 
to a great variety of work, and it can be adapted 
to suit different conditions, both as to the means 
of clamping and as to the points on which the work 
is located. Any method of clamping applied to a fix¬ 
ture which has been previously machined must take 
into consideration the fact that no distortion can 
be permitted. The use of springs and spring jacks 
for this purpose is common. Care must be exercised 
that when the set-screws are tightened they will not 
force the jacks out of position. 

Vertical Boring-Mill Fixture for a Fragile Alumi¬ 
num Casting.—One of the most difficult examples of 
a fixture for holding a piece of thin work of irregular 
shape, and machining it when held without causing 
distortion in the work, is shown in Figure 102, at 
A. In the plan above it will be seen that the cast¬ 
ing has a thin flange of approximately elliptical 
shape and the face of this flange is to be machined 
in the setting indicated. In addition to this the face, 


VERTICAL BORING MILL FIXTURES 


229 



ITC. 102. PLAN AND SECTION OF A VERTICAL BORING MILL 
FIXTURE FOR A FRAGILE ALUMINUM CASTING 


B, located below the surface of the other flange, 
must also he faced in the same operation. The part 
of the flange indicated at A is joined to the right- 
hand portion of the casting, as indicated in the sec¬ 
tional view below. The other side of the flange, how¬ 
ever, at C, is open and unsupported, making it very 
difficult to hold the piece without forcing the parts 
out of alignment. 











































































230 


TOOLS AND PATTERNS 


This piece of work is one of the most difficult that 
I have ever encountered, and I give it here simply 
to show the possibilities of arranging clamping de¬ 
vices so that they will not distort the work. The 
piece is set up with the boss, on the under side of 
B, locating in a V-block on the fixture base, and the 
edge of the adjacent flange is supported by the 
spring pins indicated at D. These spring pins are 
locked by means of the special screw, E. The flange, 
A, rests against a knife-edge locater, F, and is lightly 
clamped by means of swinging knife-edge dogs at 
G and H, while resting on the pads shown at K. 
The other side of the flange, C, is simply a rim 
which must be held and firmly located without 
springing it out of position in the slightest degree. 
For this purpose, the floating hook-bolt, shown at L, 
is made in triplicate. These bolts are used in the 
three bosses, M, N, and 0, although only one of them 
is shown in the illustration. The action of the hook- 
bolts is such that the work is clamped between the 
jaws shown while the entire mechanism “floats”, so 
that it does not strain the work. After the hook- 
bolt is tightened, it is locked in place by means of 
the set-screw, P. 

By this method of clamping, any piece of delicate 
section may be clamped without causing distortion. 
Although the example shown is a rare case, the prin¬ 
ciples involved in this design can be applied with 
equal success to other work of similar nature. It is 
sufficient to say in regard to the fixture mentioned 
that its work was in every way satisfactory and the 
work was machined without error. 


VERTICAL BORING MILL FIXTURES 231 

Simple Fixture for Machining an Eccentric—An 

example of a fixture for turning an eccentric piece 
was shown in the group of fixtures in Chapter XII, 
but in that case the work was held on a swinging 
fixture applied to a horizontal turret lathe. Another 
example of an eccentric turning fixture of the in¬ 
dexing type, but arranged for a vertical boring mill, 
is shown in Figure 103. In this case, the work is 
set up on an indexing plate, A, by means of the 
three pins, B, in the flange. This indexing plate is 
located eccentrically on a base, C, which is fastened 
to the boring mill table, being located on a plug, D, 
in the center hole. After the work is set up on the 
pins, it is clamped in place by means of the three 
hook-bolts shown at E, these bolts being brought 
down on the flange as indicated in the upper view. 
When clamped in the position shown, the hole, F, is 
bored, and then the upper part of the fixture, A, is 
swung around until the center, G, takes the place 
of the hole previously machined. A locating pin is 
provided at H to give the correct location. 

In indexing the fixture, the button clamps around 
the rim, as shown at K, and is loosened to permit 
the revolution of the portion, A; but when the table 
has been indexed to the proper position these clamps 
are again tightened before the machining takes 
place. The next operation on the work is the ma¬ 
chining of the eccentric, L, when it has been indexed 
into the position mentioned. After this the work can 
be removed from the fixture and another substituted 

for it. ... 

Work of this character is frequently machined m 


232 


TOOLS AND PATTERNS 



FIG. 103. PLAN AND SECTION OF A FIXTURE FOR AN ECCENTRIC 
PIECE OF WORK 


two settings, and no attempt is made to make an 
indexing fixture suck as that shown. In such an 
event the ordinary method of procedure is to bore 
the hole first and then locate the work on another 
fixture on a stud set eccentrically to the center for 
































VERTICAL BORING MILL FIXTURES 233 

the turning of the eccentric surface, L. The matter 
of designing a fixture for a piece of work of this 
kind is dependent entirely upon the number of pieces 
to be machined and the accuracy required in the 
finished product. Application of this principle may 
be made to many varieties of work where two sur¬ 
faces are machined eccentric to each other. 

Sliding Fixture for Boring a Pair of Cylinders.— 
When a pair of cylinders, such as those shown in 
Figure 104, at A and B, are to be bored and faced 
on a vertical boring mill, the work must be handled 
either by means of two settings, or by an eccentric 
or sliding fixture. If two settings are to be used, 
the ordinary method of handling is to machine one 
of the cylinders first and then set it up on a stud 
eccentric to the center of the table at the correct 
distance to bring the center of the second cylinder 
into position for boring. For rapid production, how¬ 
ever, a sliding fixture or one having an eccentric 
movement can be designed, so that the work can 
all be handled at one setting, thus saving consider¬ 
able time in the machining and in the handling of 
the work. 

The device shown in Figure 104 consists of a 
base plate, C, which is fastened to the table and is 
centrally located by means of the plug, D. The base 
plate is held by means of the bolt, E, in the table 
T-slot as indicated. Mounted on the base plate, C, 
is a dovetailed slide, F, on which suitable clamps, G, 
are provided to hold the work. A sectional view 
taken through the base is shown at H. Along each 
side of the sliding members are two handles, K, for 


234 


TOOLS AND PATTERNS 



FIG. 104 . SLIDING FIXTURE FOR BORING A PAIR OF CYLINDERS 

























































































VERTICAL BORING MILL FIXTURES 235 

the purpose of locking the sliding fixtures in any 
desired position. After one of the holes has been 
bored, the handles are unscrewed and the fixture is 
pushed over until the second cylinder is under the 
center of the spindle, the correct location being as¬ 
sured by means of a taper pin, L. When the de¬ 
sired position has been reached, the levers, K, are 
again tightened, and the second cylinder may be 
bored in exactly the same manner as the first. 

Threaded Knock-off Arbor for Vertical Boring 
Mill. —The work shown at A, Figure 105, is a large 
head used for a rock drill. The piece is made of 
chrome-nickel steel which is extremely hard to cut. 
The work has been previously machined on the in¬ 
side surfaces, B, and has been threaded at C as 
indicated. It is necessary to machine the outside 
tapered surfaces, A and B, in another setting, and 
these surfaces must be in correct relationship to that 
previously threaded inside of the work. A knock-off 
arbor was therefore suggested, such as that indicated 
in the illustration. 

This work was to be done on a vertical boring mill, 
and accuracy was an essential point. The base of 
the fixture, D, is located on the table of the machine 
and is held in place by means of the bolts, E, which 
pass through the T-slot in the table and are clamped 
by means of the shoes shown at F. The location of 
the plate is obtained by means of the threaded stud 
which is ground to a fit at G in the central hole of 
the table. The right-hand threaded arbor, H, is 
made at the upper part, so that the thread corre¬ 
sponds to the inside thread in the work at C. Below 


236 


TOOLS AND PATTERNS 



FIG. 105. THREADED KNOCK-OFF ARBOR FOR A VERTICAL 
BORING MILL 


this a left-hand thread is cut at K. The lower part 
of the arbor is provided with two pins, L, in order 
to give good driving properties. The knock-off por¬ 
tion of the arbor is shown at M, with a left-hand 
thread to fit the part K. 

Let it be supposed that the fixture is about to be 
loaded by attaching the piece A. At this time the 
knock-off portion, M, is screwed up until it shoulders 
against the portions N. The work, A, is then screwed 
on until it makes up against the surface 0. The 





































VERTICAL BORING MILL FIXTURES 


237 


work is now ready for machining, and during the 
action, because of the pressure of the cut, the sur¬ 
face, 0, becomes very tightly in contact with the 
knock-off pad. After the work has been done, a 
sharp blow on one of the projecting lugs of the 
knock-off, M, causes the pressure at the point 0 to 
be relieved, so that the work can be easily unscrewed 
from the arbor. The principles involved in this arbor 
are practically the same as those described in Chap- 
tei XIII, under the heading “Expanding Arbor for 
an Adjusting Nut.” 


CHAPTER XVI 


GRINDING FIXTURES 

Adaptability of Cutting Fixtures.—The functions 

of grinding as practiced by manufacturers in general 
have been taken up in Chapter VII, but the matter 
of holding fixtures for the grinding operations has 
not been dealt with to any extent. As a matter of 
fact, fixtures used for grinding purposes are very 
similar to those used in various machining opera¬ 
tions, although the necessity for holding the piece 
rigidly is not present, since the amount of pressure 
exerted on the work by the grinding operations is 
nothing like as severe as by the cutting operations. 
Many of the fixtures devised for machining opera¬ 
tions can be used for grinding, but as a rule grinding 
fixtures are considerably lighter in construction than 
those used for turning and facing. 

The principles which apply to holding devices of 
various kinds for turning can be applied to grind¬ 
ing practice, with proper modifications to suit the 
conditions. For example, there are many cases where 
a spring clamp can be used for a grinding fixture 
with excellent results, and yet such clamps would 
not be suitable in any way for machining operations 
on account of their lack of holding power. The pull¬ 
ing action of a grinding wheel taking a very light 
238 




GRINDING FIXTURES 


239 



FIG. 106. METHOD OF SETTING UP A GRINDING MACHINE FOR 
EXTERNAL CYLINDRICAL GRINDING 


cut is nowhere near as severe as when a cutting tool 
is used on the work. 

When cylindrical work is to he ground, there is 
seldom a need for any sort of grinding fixtures— 
unless some portion of the work is irregular, in which 
case a special method must he used for holding. The 
ordinary method of locating and holding a piece of 
cylindrical work for external grinding is illustrated 
in Figure 106. The work, A, in this case has several 
shoulders, B, C, and D, which are to he ground in 
the setting indicated. The work is located on the 
centers shown at E and F, and is driven hy a dog, 
G. which enters the driven faceplate, H. While the 
work is in the position indicated, the wheel, K, is 
traversed in the direction indicated hy the arrows 
until the various diameters have been ground to the 
correct size. It will he seen that no special equip¬ 
ment of any kind is necessary in performing work of 
this character. 




































240 


TOOLS AND PATTERNS 



FIG. 107. ROTARY AND RECTANGULAR MAGNETIC CHUCKS 


Magnetic Chucks. —Frequently, however, cylin¬ 
drical work requires special fixtures, for although 
the portion which is to be ground may be cylindrical, 
it may happen that the method of holding must be 
special in order to accommodate a peculiarly shaped 
piece. Chucks, either magnetic or the step-chuck 
type, are largely used for holding work which is to 
be ground. When the work permits the holding 
by magnetic chucks, this method is largely used and 
gives very satisfactory results. Otherwise, a step- 
chuck can be arranged to handle the work. 

A group of magnetic chucks, made by the Heald 
Machine Co., is shown in Figure 107. Those shown 
at A and B are of the rotary type, while those shown 
at C, D, and E, are of the rectangular type, not used 
on rotary machines, but applied principally to sur¬ 
face grinding. One of the great advantages de¬ 
rived from the use of magnetic chucks is the rapidity 
with which the work is applied to and removed from 
the chuck. Another advantage lies in the fact that 
there is little danger of distortion caused by an im- 



GRINDING FIXTURES 


241 


proper method of clamping. This feature is par¬ 
ticularly noticeable when thin work is to he ground. 
Still another advantage is that a great number of 
pieces can be held at the same time. It is only nec¬ 
essary to throw a switch in order to apply the elec¬ 
tric current, magnetize the soft iron core of the 
chuck, and hold rigidly any work on its surface. 

The rotary chuck, shown at A and B, can be 
applied to a horizontal machine for cylindrical 
grinding, or to a rotary surface-grinding ma¬ 
chine. Piston rings or packing rings, for example, 
are usually ground on their edges on this type of 
chuck. The rectangular type of chuck, shown at 
C, D, and E, is particularly suited to surface grind¬ 
ing and to milling or planing operations. In applica¬ 
tion they hold a number of small pieces or a single 
piece of long work. 

Many uses will be found for these chucks in a 
manufacturing establishment, and the type of chuck 
most suited to any man's work can best be deter¬ 
mined by consultation with the various manufac¬ 
turers. Suitable demagnetizers are applied to all 
chucks of the magnetic type, so that after the. work 
has been removed, no future trouble is experienced 
from magnetism remaining in the work. 

Grinding Fixture for Universal-Joint Part.—A 
number of pieces in an automobile are made of alloy 
steel that requires special methods of hardening. One 
of these pieces is the rocker arm of the universal 
joint, shown in Figure 108 at A. This piece must be 
ground on the two cylindrical portions B and C, and 
it requires a special fixture as indicated at D. This 


242 


TOOLS AND PATTERNS 



FIG. 108. FIXTURE FOR GRINDING UNIVERSAL JOINTS 


fixture is not designed for the purpose of holding the 
work, but merely to provide a means for driving 
the long end, A, and preventing vibration of the 
work during the process of grinding. Such a fixture 
as this can be mounted on an adapter plate, as at E, 
attached to the spindle of the machine and rotated. 

The work in Figure 108 is held on the faceplate, 
and is located on two centers, as indicated. A suit¬ 
able thumb screw is provided at F on the fixture, so 
that when the work is placed in position the thumb 
screw can be tightened to throw the work over 
until it strikes a stud, G. Since this fixture with 
the work in position is heavier on one side than on 
the other, a cast-iron lug, H, is applied to the oppo¬ 
site side, as shown, so that the entire fixture can be 
properly balanced before the work 'is done. If a 
grinding fixture of this sort were to be made up and 
not properly balanced, the action on the entire ma¬ 
chine would be injurious and the work produced 
would not be true. It is not only advisable but nec¬ 
essary to see that any fixture used for grinding is 
properly balanced to obtain the best possible results. 


















GRINDING FIXTURES 


243 



Piston Grinding Fixtures. —Manufacturing prac¬ 
tice differs in regard to the finishing of automobile 
engine pistons, but most makers finish the external 
surface of the piston by grinding. When this is done, 
accuracy can be more readily kept within the re¬ 
quired limits, and the superior finish gained by the 
grinding is an added advantage. 

A fixture for holding an automobile piston while 
grinding is shown in Figure 109. In this case, the 
work, A, is located on an arbor, B, which is drawn 
back into a tapered hole, C, in a special nose piece, 
D, which is screwed to the end of the last spindle, 
e! A key to hold the work on the spindle is pro¬ 
vided at F, somewhat unnecessarily in the instance 
shown. I say unnecessarily, because the amount of 
friction generated by the grinding wheel against the 
outside of the piston, A, could never be sufficient 
to permit the arbor, B, to turn in the tapered hole, 













































244 


TOOLS AND PATTERNS 


especially when drawn back by means of the nnt 
and washer shown at G. The end of the piston is 
given additional support by means of the center 
shown at H, this center being in the tailstock of the 
grinding machine. The method of holding the pis¬ 
ton on the arbor is somewhat out of the ordinary 
and is therefore worthy of description. 

The open end of the piston locates on the arbor 
at K, and is drawn back firmly against the shoulder, 
L, by means of the rod, M, and the taper wedge, N. 
When the work is placed in position, the ball-ended 
plug, 0, is dropped through the wrist-pin hole, P, 
passing through the draw-back rod as indicated. 
After this has been done the wedge, N, is pushed 
lightly into place until the operating rod, M, draws 
back on the pin, 0, to carry the work up against 
the shoulder, L, where it is held firmly. A slot is 
cut in the pin, 0, as indicated at Q, so that the re¬ 
taining pin, R, will prevent it from falling out of 
the work. The purpose of the spring indicated at S', 
is to force out the rod, M, after the work has been 
done and when the wedge, N, is pushed back. A 
grinding fixture of this sort can be applied to many 
varieties of work with suitable adaptations to con¬ 
form to the style of work to be gound. 

Internal Grinding Fixtures—A Rail-Bearing Cage. 
—Let it be assumed that the work A, Figure 110, has 
been previously machined at all necessary points, has 
subsequently been hardened, and that it is now neces¬ 
sary to grind the hole, B, in correct relation to the 
cylindrical surface, C. In actual operation, the hole, 
B, is ground to size first, and the work is then placed 


GRINDING FIXTURES 


245 



FIG. 110. FIXTURE FOR INTERNAL GRINDING A BALL-BEARING CAGE 

on an expanding arbor and the surface, C, is ground 
in the correct relation to the hole, B. The fixture 
used for grinding the hole, B, was originally made 
up for boring and turning, but was later adapted to 
the present use. Since the fixture was made up for 
a heavier variety of work than a grinding operation, 
the clamps shown at D are much more suited to a 
turning operation than they are to a grinding fix¬ 
ture; so, also, the driving pin shown at E would 
usually be considered unnecessary if the fixture were 
made up for a grinding fixture. This example is 
given principally to show how a fixture made up 

















































246 


TOOLS AND PATTERNS 


for turning and boring can be adapted to a grinding 
operation if necessary. 

If this fixture bad been designed originally for 
grinding, spring clamps could have been used in 
place of the straps shown at D, and the driving pin, 
E, could have been omitted. In addition to this, the 
entire fixture could have been made much lighter 
in its general construction, and would have answered 
the purpose fully as well. The adapting plate, F, 
was made up in this particular case to fit the spindle 
of the grinding machine, and the faceplate, G, was 
fitted to it as indicated. A special form of chuck, 
having a series of jaws and operated by means of a 
draw-in mechanism through the spindle, can often 
be used for work similar to that shown. An example 
of this type of holding device is described later in 
this chapter. 

Grinding Fixture for Universal Joint Member.— 

A good example of a fixture used for grinding a 
tapered hole is shown in Figure 111. This fixture 
has a number of commendable points, one of which 
is that it may be adjusted to take care of slight 
variations caused by distortion in hardening the work 
previous to the grinding operation. 

The method of setting up the work in this instance 
is rather out of the ordinary. In the first place the 
work requires that the tapered hole, A, must be 
ground concentric with the hole, B, and at right 
angles to the cross-hole, C. For this reason the work 
is located on a sliding rod, D, which has a bearing 
in the spindle at E, so as to run concentric with the 
spindle. A shoulder, B, on the rod, D, locates the 


GRINDING FIXTURES 


247 



FIG. 111. GRINDING FIXTURE FOR A UNIVERSAL JOINT MEMBER 


work in a central position. After it is so located, 
the hardened and ground bar, F, is passed through 
the cross-hole, C, after which the washer, G, is 
slipped into place and the draw-back rod, D, oper¬ 
ated from the rear end of the spindle, pulls back 
the work until the bar, F, seats itself in the two 
V-blocks, H, on the fixture. (The small detail shown 
below the illustration indicates the method by which 
the bar, F, is located in the V-block.) 

A refinement provided on this fixture is the 
knurled button, L, whereby variations in the work 
can be compensated. There are three of these but¬ 
tons located 120 degrees apart on the face of the 
fixture, but only one of them is shown in the illus- 













































248 


TOOLS AND PATTERNS 


tration. An indicator may be nsed in the hole, A, 
to approximate its truth before the grinding takes 
place, and these buttons can then be set up to bring 
the hole in the desired position. After the work 
has been properly set, it is ground by the small 
grinding wheel shown at M, using an internal grind¬ 
ing attachment or an internal grinding machine for 
the work. Applications of the principle shown may 
be used for other cases of similar character. 

Adaptable Fixture for Grinding Spur Gears. —After 
a spur gear has been machined and the teeth have 
been cut, it is frequently put through a process of 
pack-hardening or treating in some way to produce 
a hard and, at the same time, a tough texture to the 
metal, so that it will withstand abuse without frac¬ 
turing. During the process of hardening there is 
likely to be a slight change in the shape of the 
work, and as it is essential that a gear should have 
its teeth cut in correct relation to the center hole, a 
method of compensating for any error from the 
hardening process is highly desirable. 

The work, A, shown in Figure 112, is a spur gear 
which has been hardened and in which it is desirable 
to grind the hole, B, which will be concentric with 
the teeth around the periphery of the gear. To as¬ 
sure this result the method of locating the gear must 
be determined either by the pitch line of the teeth 
or else from the bottom of the teeth, for there is 
little likelihood that these points will change their 
relation to the center of the gear because of distor¬ 
tion in hardening. For a spur gear the bottom of 
the tooth is usually selected as the locating point. 


GRINDING FIXTURES 


249 



FIG. 112. SECTION AND PLAN OF AN ADAPTABLE FIXTURE FOR 


GRINDING SPUR GEARS 

The fixture shown in the illustration consists of a 
nose piece, C, mounted on the spindle, D, and pro¬ 
vided with a tapered portion, E, as indicated. The 
gear is held and located by a series of blocks, F, 
each of which has a point, G, so designed that it 
will strike the bottom of six teeth, as indicated. 
These six blocks are radially located in a split mem¬ 
ber, H, by means of the clamps shown at K. This 
split member, H, is slotted in six places in order 
to allow it to contract as it is pulled back into the 
tapered portion, E, by means of an internal mech¬ 
anism running through the spindle as indicated at 
L, A spider-shaped piece, M, is set into the base 
piece, C, between the slots, N, which provide for ex¬ 
pansion and contraction of the piece, H. This spider 
is provided in order to give an endwise location to 
the work. 

It will be seen that as the work is placed in the 
chuck, the points, G, are drawn in radially until they 
center the work from the bottom of the six teeth 
as indicated. This mechanism may be applied to a 














250 


TOOLS AND PATTERNS 



FIG. 113. ADJUSTABLE FIXTURE FOR GRINDING A BEVEL PINION 


gear having an odd number of teeth by making up 
the blocks to suit the conditions. 

Adjustable Fixture for Grinding a Bevel Pinion.— 
A bevel gear that has been hardened is subject to 
the same changes as those that may be produced in 
a spur gear. It must, therefore, be set up for the 
grinding operations in such a way as to compensate 
for any errors caused by the hardening process. In 
this case, the pitch line of the gear is generally used 
as a locating point. Taking the example shown in 
Figure 113: the work, A, is to be ground in the 
tapered hole, B, which must be concentric with the 
teeth cut on the outside of the gear. 

A different type of fixture is provided for this 
class of work. A special nose piece, C, is screwed 
to the end of the spindle in the usual manner, and 
is provided with four holes, D, in which are inserted 
the round wires, E, which pass through rollers, F, 



























GRINDING FIXTURES 


251 


and rest against a hardened ring, G, located in the 
nose piece and having a suitable taper so that the 
center line of the roller will adapt itself to the pitch 
line of the gear. 

An enlarged view of one of these rollers is shown 
in section at the lower part of the illustration. It 
will be seen that the center hole through the rollers 
is tapered for clearance only, so that a floating action 
is permitted, allowing them to adapt themselves to 
the gear. Provision is made for supporting the wire 
at the inner end of the chuck by means of the ring, 
H, and suitable holes are drilled to receive the ends 
of the wire. When setting up the work, A, it is 
placed in the chuck, and the various rolls find their 
location on the fixed line of the gear. The spring 
clamps, K, are then swung around into position to 
hold the gear in this location. The work is then 
ready for grinding. 

This type of fixture also can be adapted to bevel 
pinions of odd or even teeth by slight changes in 
the roll location and by suitable rings of the correct 
angle, as shown at G. 

Grinding Fixture for a Large Bevel Spring Gear. 

The bevel ring gear used in the rear axle of an auto¬ 
mobile is likely to change somewhat during the hard¬ 
ening process; and it is essential, therefore, to grind 
it after hardening in such a way that the teeth and 
the center hole will be in correct relation to each 
other. For this purpose a fixture can be made up 
for grinding similar to that shown in Figure 114. 

In this case, the work is located by means of a 
master gear, shown at A in the figure. This master 


252 


TOOLS AND PATTERNS 



FIG. 114. GRINDING FIXTURE FOR THE LARGE BEVEL RING GEAR IN 
THE REAR AXLE OF AN AUTOMOBILE 


gear is an exact duplicate of the gear which is to 
be ground, and is fastened to the faceplate shown 
at B, so that the pitch line of the master gear is 
concentric with the center of the spindle. In opera¬ 
tion, the work, C, is placed in position against the 
face of the master gear and with the teeth between 
those of the master gear. As each of the gears is 
beveled, the bevels act in such a way as to center 
the gear in the correct position. After the location 
has been assured, the spring clamps, D, are adjusted 
to hold the work properly. As little pressure is re¬ 
quired to hold a piece of work of this kind, these 
clamps answer the purpose very well and can be 
quickly adjusted to position. The principle shown 
here can be adapted to any work of this character 
and the work obtained by its use gives excellent 
results. 









































CHAPTER XVII 


OPEN DRILL JIGS 

Functions and Operation.—Strictly speaking, a 
drill jig is a device by means of which a piece of 
work may be properly located and clamped in order 
that a series of holes may be drilled in the work at 
certain fixed locations. It will be seen, then, that any 
number of pieces of similar shape and form can be 
placed one after the other in a drill jig and all the 
pieces will be made in such a way as to be inter¬ 
changeable. Not only is a drill jig provided with 
the proper methods of clamping and holding the 
work, but there are also a number of bushings, cor¬ 
responding to the number of holes in the piece, 
located in the jig in such a way that the drills used 
in the manufacture will pass through these bush¬ 
ings and be guided thereby. The bushings are made 
of hardened tool steel, and are located very care¬ 
fully by a toolmaker in their correct positions to 
produce the holes desired. 

Naturally, the shape of the work to be held exer¬ 
cises a powerful influence on the form of jig to be 
designed for the work. It is evident that a jig for a 
simple piece of work which can be held easily by a 
couple of simple clamps, is much easier to design 
than one which is of such shape as to require very 
253 


254 


TOOLS AND PATTERNS % 


special methods of locating and clamping. In order 
to illustrate the functions of a drill jig, let us suppose 
that a hole is to he drilled in each end of a simple 
lever, and that the work is to he done in a drill jig. 
Let us further suppose that the workman has a drill 
jig before him on the table of a drill press, and that 
he is ready to do the work. He takes the work in 
one hand, then, and places it in position in the drill 
jig, clamping the work securely by means of the 
clamps provided in the jig. After this he pulls the 
drill jig under the drilling-machine spindle, or 
spindles, and proceeds to feed the drill down through 
the bushings provided for it in the jig. After the 
drill has been pressed through the work to the proper 
distance, the workman raises the spindle, removes 
the jig to a convenient position on the table, and 
releases the clamps which hold the work in place. 
This allows the piece to be taken out of the jig and 
replaced by another one, and the process is repeated. 

When drill jigs are to be made for large work, or 
when a number of holes are to be drilled at different 
angles or from different sides, it is necessary to 
make up a drill jig of more elaborate form. If the 
work is very large and heavy, trunnion jigs are 
frequently employed. Jigs of this character are so 
made that the work is placed in position, clamped, 
and the entire jig is revolved on a bearing at each 
end, this bearing being the term from which the 
word trunnion is derived. A trunnion jig is mounted 
on a pedestal, or base of some kind, in such a way 
that it can be swung into the correct position for 
drilling. It is also provided with suitable indexing 


OPEN DRILL JIGS 


255 


mechanisms, in order to locate the jig properly at 
the various angles in which it is to be drilled. Some¬ 
times trunnion jigs are mounted on a sort of carriage 
which can be rolled from one drill-press table to 
another, in order to take advantage of special group¬ 
ing of the spindle. 

In regard to the grouping of spindles, it must be 
remembered that many drill jigs are used on mul¬ 
tiple-spindle drilling machines. A number of drilling 
machines of this character can be arranged one after 
the other and connected by means of a track or 
miniature railroad on which a trunnion jig, suitably 
mounted on a carriage with wheels which tit the 
rails of the railroad, can be rolled from one machine 
to the other and indexed, as previously mentioned. 
An arrangement of this sort can be used for such 
work as an automobile cylinder or crank-case, or a 
machine-tool gear box, or some other piece of work 
that requires a number of holes to be drilled in it 
from different sides. The advantage of such a jig 
is that the work is once clamped in position and is 
not released until all of the holes have been drilled. 
In this way, the jig makes it possible to obtain a 
number of pieces of work, all of which are drilled 
in exactly the same relation to each other. Drill 
jigs can be designed so that their work can be done 
on any type of drill press, from a single-spindle ma¬ 
chine to one of the multiple type. 

A number of points must be considered in the de¬ 
sign of a drill jig: the method of locating the work 
in position; the method of clamping it so that it will 
be firmly held against the pressure of the drill and 


256 


TOOLS AND PATTERNS 


at the same time will not be distorted by the pressure 
of the clamp; clearance around the work; provision 
for chips; easy accessibility for cleaning so that no 
variation in the work can be caused by chips or their 
accumulation on the locating point; and finally a 
method of clamping which will be both rapid and 
positive in action. 

When a series of jigs is to be made, these points 
must all be taken into consideration if the jigging 
process is to give correct results. Any incorrect 
method of locating, or any method of clamping which 
tends to distort the work, may cause a great deal 
of trouble and expense; for even with work requiring 
great accuracy it is entirely possible to drill a series 
of holes in such a way that they will not coincide 
with other holes to which the work is to be fitted. 
Again, if the work is strained by the method of 
clamping, the hole will not line up properly with 
the other work and a great deal of unnecessary fit¬ 
ting must be done when the parts are assembled. 

In taking up the more common types of drill jigs, 
let us consider that the two most general types are 
the open and the closed jigs. An open jig is one 
in which the work is held in such a way that it is 
not enclosed. A closed jig is one of the box type, 
where the work is placed in a sort of box or frame 
and is usually drilled from several sides in the same 
setting. 

A Simple Plate Jig.—The work shown at A, Figure 
115 , is a cast-iron flange which is to be drilled with 
six holes, B, located in a circle around one face of 
the flange. This is an extremely simple piece for 


OPEN DRILL JIGS 


257 



which to make a jig and, therefore, it is used as an 
example to show what simple forms may be used for 
jigging purposes. 

In this case, the work has been previously bored 
and reamed, so that the jig plate, C, can he located 
directly on the upper flange by means of a plug, D, 
which enters the roll. The jig plate is provided with 
a series of bushings, E, so located in the plate as to 
give the resired location to the hole. For a piece 
of work of this kind no clamping device is necessary, 
as the work is usually done on a multiple-spindle 
drill press, each spindle of which contains a drill of 
the proper size for the work. These drill spindles 






























258 


TOOLS AND PATTERNS 


are adjustable, so that they can readily be made to 
correspond to the holes in the jig. In operation, a 
jig of this kind is simply dropped on the work which 
is located on the drill press table, and immediately 
thereafter the spindles of the drill press are brought 
down until they enter the bushings; after this the 
feed is started and the work is completed without 
any clamping device being necessary. The pressure 
of the drill is sufficient to hold the work in position, 
and after the holes have once been started there is 
no necessity for any method of clamping to keep the 
jig properly located. Jigs of this kind are suited 
to many kinds of work that have been previously 
machined, as indicated, and also to work that has a 
finished face on which to rest it while the drilling 
is taking place. 

Plate Jig with Supplementary Supporting Ring.— 

Another type of plate jig, more suited to work that 
would be unstable without support while being 
drilled, is shown in Figure 116. This piece of work 
has been previously finished on both sides of the 
flange, B, and also on the outside of the hub, C. It 
will be seen, however, that the piece could not be 
drilled very well without some sort of support, be¬ 
cause the radius of the hole, E, is out beyond the 
base of the hub, A, and if the work were to be drilled 
without any support, it would be likely to tip one 
way or the other unless all the drills were exactly 
of the same length. In order to overcome any 
tendency of this sort, a cast-iron ring, F, is made to 
act as a support for the work. This ring is made of 
sufficient diameter and stability to allow the work to 


OPEN DRILL JIGS 


259 



FIG. 116 . PLATE JIG WITH SUPPLEMENTARY PLATE 


rest on the flange at B and be supported thereby. 
The drill-jig plate, D, in this case, is made so that 
it will slip over the hub, C, and is provided with a 
series of bushings, E, arranged in circular form to 
give the correct spacing of the holes. 

In some cases, the holes to be drilled may be of 
several diameters, and drills of corresponding diam¬ 
eter are used. However, when an occasion of this kind 
arises, some method of location must be provided, both 
for the work and for the drill-jig plate in order that the 
correct bushings may be located properly under the 
corresponding drill. 

This kind of jig is usually used on a multiple- 
spindle drill press, with the spindles grouped to the 
correct radial setting. Adaptations of the two forms 
of jigs just mentioned, Figures 115 and 116, may be 
made to cover a variety of cases. Such jigs are 






























260 


TOOLS AND PATTERNS 



FIG. 117 . DRILL JIG FOR AN OIL-PUMP COVER 

cheap in their construction and answer the purposes 
for which they are intended very well indeed. 

Drill Jig for an Oil-Pump Cover. —The work shown 
at A, Figure 117, is an aluminum oil-pump cover 
which has been previously faced on the surface, B, 
but has not been turned. Due to the fact that only 
one surface on this piece has been machined, it is 
necessary to locate from this surface for the opera- 






































OPEN DRILL JIGS 


261 


tion of drilling the six holes shown at C. In order 
properly to accomplish a correct location for this 
work, the vee principle is used. 

In the example shown in Figure 117, the two pins 
at D are used as locaters of this kind. The work is 
forced against or between these pins by means of the 
thumb screw shown at E, and is further located by 
means of the stop-screw, F, against which the boss 
is clamped by means of another screw, G. The 
clamps, H, are then tightened, thus holding the work 
firmly against the face of the fixture and down on 
the surface, B. With the work in this position, the 
entire jig is turned over onto the legs, K, on which 
it rests while the drilling operation takes place. 
These legs are a part of the base casting of the jig, 
and are surfaced in such a way as to provide an ample 
means of support which is, at the same time, parallel 
with the surface, B. Bushings are provided for the 
holes at C, as in the former instances described. It 
will be seen that after the jig has been turned over, 
the pressure of the drills comes entirely against the 
clamps. H. These clamps, therefore, must be suffi¬ 
ciently strong and heavy to withstand the pressure. 

Jigs of this kind are very useful for many kinds 
of semi-cylindrical work where there is a single fin¬ 
ished surface and a series of holes arranged more or 
less centrally about the center of the piece. Applica¬ 
tions of the principles shown in this jig can be made 
to a great variety of work. _ . 

Open Jig for a Lever. —Jigs designed for drilling 
holes in levers are of two kinds: those which locate 
from the work in its unfinished state or which locate 


262 


TOOLS AND PATTERNS 



FIG. 118 . OPEN JIG FOR A LEVER 


on bosses at either end of the lever; and those which 
locate for a single drilling operation of one end-hole 
from a previously bored or reamed hole in the other 
end. Both of these jigs are in common use and will, 
therefore, be described separately. The type men¬ 
tioned first is shown in Figure 118. In this case the 
lever, A, has been finished by straddle milling the 
side of the bosses at each end. The jig shown is for the 
purpose of drilling the two holes, B, at each end of 
the lever. 

The method of locating used for this piece is a 
vee block, C, in which the boss at one end of the 





















































































OPEN DRILL JIGS 


263 


lever rests. The other end of the lever is located 
and clamped simultaneously by means of the sliding 
vee-block, D. This vee-block is chased up into posi¬ 
tion by means of the thumb screw, E, located in a 
swinging latch, F, between the bosses, G, through 
which a pin is passed. An additional support is 
given the latch at the other end on the lug, H. After 
the work has been located as mentioned, it is clamped 
firmly by means of the wide clamp, L, which is 
slotted so that it can be pushed back out of the way 
to allow the piece to be placed in position. When 
the work has been clamped as indicated, the entire 
jig is turned over, so that it rests upon the two feet, 
K, after which the holes are drilled through the bush¬ 
ings indicated. 

This type of jig is in common use, with certain 
modifications in regard to clamping and locating in 
accordance with the nature of the piece to be drilled. 
It is comparatively inexpensive and gives excellent 
results. 

Open Jig for a Lever with Stud Locater. —The 

lever, A, Figure 119, is of similar shape to that shown 
in Figure 118, but it is of larger size, and the end, B, 
has been bored and reamed in a previous operation. 
It is, therefore, necessary to locate from this hole to 
drill the small end, C. A stud, D, is placed in the 
jig body, and the work is placed over it as indicated. 
The small end, C, is located by means of a sliding 
vee-block, E, which is forced up against the boss by 
means of a thumb screw, F. The work is held in 
position and supported against the pressure of the 
cut by means of the clamp shown at G. As in the 


264 


TOOLS AND PATTERNS 



former case, after the work has been located in the 
jig it is turned over, so that it rests upon the feet, K, 
in which position it is drilled. Jigs of this kind are 
nearly as common as that shown in Figure 118, and 
their application to many shapes of levers will be 
apparent. 

Open Jig for a Small Bracket. —The work shown 
at A, Figure 120, is a small bracket which is to be 
drilled at B, C, and D. The holes, B and C, are in 
one plane, and the hole, D, is in another. Therefore, 
the jig must be so made that it can be turned on one 
side for the latter hole and on another side for the 
holes at B and C. The use of a vee-block is seen in 
this fixture at E, and the rounded angular end of the 




























































OPEN DRILL JIGS 


265 



work rests in this block as it is forced there by means 
of the set-screw shown at F. It will be seen that this 
set-screw is placed at an angle and also that the vee- 
bloek, E, has an angular face. The purpose of this 
is to make sure that the work will be held down 
firmlv and located correctly. The work rests on the 
flat milled surface, G, and suitable bushings are pro- 
vided for the various holes. An additional clamp is 
provided at H in order to make the clamping action 
more positive. Legs are provided on the side of the 
jig at K and also at L, so that the work can be 

































































266 


TOOLS AND PATTERNS 



FIG. 121 . SET-ON JIG FOR A TRANSMISSION-CASE COVER 


drilled in the correct positions. Additional legs are 
also made at M for purposes of setting up the work. 

Set-on Jig for a Transmission-case Cover. —When 
a large piece of work is to he handled and a small 
portion of it only is to he drilled, a set-on jig is ad¬ 
vantageous. In the design of a jig of this kind it is 
always necessary to consider the hearing which the 
work itself will have on the table of the drill press, 
in order that the pressure of the drills as they enter 
the work may not be in such a position as to cause 
the work to topple over or tip on one side. 

An example of this kind is shown in Figure 121. 
In this case, the work, A, has been previously fin¬ 
ished by milling along the surface, B, and also on 
the face, C. At C, four holes are to be drilled as 

























OPEN DRILL JIGS 


267 


shown at E in the upper view. The surface, B, is 
sufficiently solid to rest on the drill-press table with¬ 
out difficulty. 

The drill jig is made of cast iron and consists of a 
pipe, D, with lugs at each end through which the 
set-screws, F, are passed to act as an end-stop for 
the jig when it is placed in position on the work. 
Another stop-pin is placed on the other side of the 
jig plate, as shown at H in the upper view, and in 
placing the jig plate on the work this pin is brought 
up against the side of the work before the set-screw, 
shown at G, is tightened. As this set-screw is tight¬ 
ened it will be seen that the entire jig is clamped in 
place on the top of the work. The jig plate is pro¬ 
vided with a series of bushings, E, through which 
the drills are passed as the four holes are drilled. 
This is a very simple type of jig, but application of 
the principle shown can be used on many other cases 
for work of similar kind. 

Set-on Jig for a Gas-Control Plate.— Set-on jigs are 
sometimes used for small as well as for large pieces 
when the size of the work is such that it can be used 
to advantage. In designing a jig of this kind care 
must be exercised to see that there is sufficient stabil¬ 
ity to the work itself to permit placing and support¬ 
ing the jig upon it. Figure 122 is a very good ex¬ 
ample of a piece of work which can be drilled with 
this type of set-on jig. The gas-control plate, A, 
in this case, has been finished in a previous opera¬ 
tion, so that the surface, B, is perfectly plane and 
can therefore be used for setting up the work. The 
jig is placed on the top of the piece as indicated in 


268 


TOOLS AND PATTERNS 



the illustration, and the two pins, shown at C, in 
reality form a sort of V against which the work is 
forced by means of the set-screw at the other end 
of the jig. This set-screw, D, forces up the work 
and locates it at the same time by means of the vee- 
block, E. A series of bushings are arranged to drill 
the holes, F and G, in the top view. 

It will be seen that when this jig is to be used, it 
is only necessary to place it in position on top of 
the work while the work is resting on the drill press 
table and then to tighten the thumb-screw, D. After, 
this has been done the jig can be readily moved 
under the spindles of the drill press, in which posi¬ 
tion the work can be drilled without difficulty. 

The number of other jigs which could be classed 
under the heading of open jigs, is so great that it is 
out of the question to enumerate the different types 

































OPEN DRILL JIGS 


269 


in a book of this kind. My effort, therefore, has 
been to show new forms of open jig, in order that 
the discriminating reader may be able to form an 
idea of the various types and their application to 
work of ordinary nature. Speaking broadly, an open 
jig can be made for almost any piece of work when 
holes are to be drilled from not more than three 
directions. As the usual thing, however, open jigs 
are designed for pieces that are to be drilled in one 
or two directions only 


CHAPTER XVIII 


CLOSED JIGS 

Bushing for an Oil-Pump Shaft. —In the previous 

chapter a few varieties of open jigs were described, 
but by no means all types were mentioned. In this 
chapter, also, it will be impossible to enumerate every 
type of closed jigs, and yet an attempt will be made 
to cover the subject in a broad way, so that the 
reader will be able to get a good idea of the variety 
of jigs. 

Referring to Figure 123, let us assume that the 
bushing shown at A, has been previously bored and 
reamed in the hole, C, and that the end, B, has been 
faced. Let us also assume that the outside of the work 
has been completely finished to the form shown, and 
that the upper end has also been faced. The work 
in this case is located on the previously finished hole 
at C on a small stud, and it rests against the sur¬ 
face, B, on the locating stud. While in this position, 
it is clamped by means of the set-screw shown at H. 
A button on the end of the set-screw bears against 
the end of the piece. 

This type of jig is arranged in such a way that 
holes can be drilled in the work at two different 
angles. The jig is turned over on the legs, F, while 
the hole located by the bushing, D, is drilled. After 
270 


CLOSED JIGS 


271 



this is done, the jig is turned over until it rests 
upon the legs, K. In this position, the drill is guided 
by the long bushing shown at G. As this bushing 
is so very long, it will be noticed that it is relieved 
to a size a little larger than the drill for a good pro¬ 
portion of its length. 

As the piece of work shown in this illustration is 
cylindrical in its general form, it does not make any 
difference how it is located radially, so that it is 
only necessary to slip it on to the stud and tighten 
the clamp screw, H, before starting the work. A 
drill jig of this kind can be used for many kinds, of 
bushing work when oil holes or other holes of sim¬ 
ilar kind are to be drilled. It forms an excellent 
example of a simple type of closed jig. Naturally, 
such a jig is used on a drill press, either with a 
couple of spindles in which the different size drills 










































272 


TOOLS AND PATTERNS 


are placed and used one after the other, or else a 
magic chuck or its equivalent is used in a single 
spindle machine, and sockets for each of the drills 
are provided so that one can he interchanged for the 
other while the spindle is in motion. 

Drill Jig for a Rod-Supporting Bracket. —The sup¬ 
porting bracket for a rod or shaft, shown at A, Fig¬ 
ure 124, has been previously machined in a hole 
which extends entirely through the hub indicated. 
At the time when the hole was reamed, the end of 
the hub was also faced. In a subsequent operation 
the surface, K, was milled in a definite relation to the 
reamed hole. In the operation indicated by this jig, 
the work to be done is the drilling of the two holes, 
B, and also the one from the opposite side as indi¬ 
cated at C. 

As the hole, F, shown entirely through the hub 
has been previously located from the milled surface, 
K, when it was machined, it is obvious that a loca¬ 
tion from the hole and the milled surface can log¬ 
ically be considered as the correct method of locat¬ 
ing for the present operation. In order to support 
the flanges while they are being drilled, the two set¬ 
screws, E, operated by the workman’s fingers are 
used. These set-screws are conical on the end, so 
that they set up a slight wedging action and hold 
the work securely. The piece is slipped upon a locat¬ 
ing stud in the large hole, and after it has been 
clamped against the opposite end of the hub by 
means of the C-washer shown at F, by the nut indi¬ 
cated, the set-screws, E, are tightened as previously 
mentioned. When drilling the holes, B, the jig is set 


CLOSED JIGS 


273 



FIG. 124 . DRILL, JIG FOR A ROD-SUPPORTING BRACKET 































































































274 TOOLS AND PATTERNS 

up upon the legs, D. When the hole, C, is to he 
drilled, the entire jig is turned over until it rests 
upon the legs on the opposite side. This completes 
the drilling operations on this piece of work. 

This is one of the simplest types of jigs which can 
be devised, but it can be made to give excellent re¬ 
sults in ordinary practice. A point which should be 
mentioned in connection with a jig of this sort is that 
the surface on the jig shown at K should be so milled 
in relation to the center stud on which the work 
locates that there will be a slight amount of clear¬ 
ance between the surface of the piece and the pad 
on which it locates. A very slight amount of tipping 
may be caused when the thumb-screws, E, are tight¬ 
ened; but in actual practice this amount would never 
be sufficient to cause any trouble, so that the jig can 
logically be considered of good design. In addition, 
this jig is easily made and easily cleaned, and chips 
are not likely to accumulate on the locating point, 
thereby causing errors in locating. 

Jig for Automobile Hand Lever. —Sometimes an 
occasion arises to make a jig which can neither be 
considered an open jig nor yet a closed jig. Such an 
example is indicated in Figure 125. In this example, 
the jig is a kind of half and half type, and is not 
really one of the two types, but is midway between 
them. In this case, the work, A, is a hand lever 
used for operating a pull rod or latch on the brake 
lever of an automobile. Previous to the operation 
of drilling, the work has been milled on the surface, 
F, and it is therefore safe to use this surface as a 
locating point in the drilling operation. The piece, 


CLOSED JIGS 


275 



FIG. 125 . JIG FOR AN AUTOMOBILE HAND LEVER 


therefore, is laid on the surface, F, in the jig as indi¬ 
cated, and is pushed over into a vee-block, D, by 
means of the set-screw, E. This set-screw strikes 
against a corner or fillet on the lever in such a way 
as to force the work into the vee-block and at the 
same time to throw it over until it strikes the end 
of the set-screw, G. It will be seen that then the 
set-screw, G, acts as one side of a vee, the other side 
of which is formed by the thumb-screw, E. All of 





























276 


TOOLS AND PATTERNS 


the clamping action is accomplished by means of this 
one screw in the case mentioned. Little difficulty is 
experienced in setting up the work for the operation 
and in obtaining a correct location. 

The work which is to be done in this setting of 
the piece is the drilling of the two holes, B and C, 
and the entire jig is set up on the leg shown at E, in 
the lower portion of the illustration, when the work is 
done. Bushings, naturally, are provided at B and C 
to guide the drill and to insure correct locations for 
the hole. 

Nearly all of the jigs shown so far in these two 
chapters are made of cast iron, as this material lends 
itself to a variety of forms and can be made cheaply 
and quickly. But the same types of jigs can be 
built up from steel if desired, and in the case of gun 
jigs and of jigs for use with a great many dull pieces, 
the steel built-up jig is to be preferred. Its cost, 
however, is prohibitive in anything but very large 
production. 

Drill Jig for a Bearing End-Cap. —When a piece 
of work has been previously machined and it is nec¬ 
essary to locate it for a drilling operation subsequent 
to the other operations on the work, it is essential 
to locate the piece by means of the finished surfaces. 
An excellent jig for a piece of work of this kind is 
shown in Figure 126. In this case the work, A, has 
been previously faced at B and has been recessed 
at C. It is necessary then to locate the work for 
the drilling of the four holes shown at F, by the 
previously finished surfaces. The method of doing 
this is to set the work upon a shallow stud or plate, 


CLOSED JIGS 


277 



FIG. 126. DRILL JIG FOR A BEARING END CAP 


locating it by means of the recess at C, and clamping 
the work by means of an equalizing collar, H, oper¬ 
ated by the thumb screw, K. . 

In placing the work in the jig, the square side o± 
the piece strikes against the two set screws, G, thus 
giving a squaring-up effect. It will be seen that the 






































278 


TOOLS AND PATTERNS 


action of the clamp collar, H, is such that when the 
thumb screw, K, is tightened, the entire collar rocks 
sufficiently to permit an equally distributed pressure 
on the work. The thumb screw, K, is mounted in a 
strap, N, which extends entirely across the jig. This 
strap is slotted at L and M in such a way that it 
can be quickly removed when placing a piece of 
work in the jig or removing one from it. 

In operation the jig is set up on the four legs 
shown at D, and the work is slipped into position. 
After this is done the strap is put in place and the 
thumb screw, K, is tightened. The entire jig is then 
turned over until it rests on the legs, E. Bushings 
are provided at P to guide the drills to their proper 
positions. 

This type of jig can be used for many varieties 
of work of a similar character, the only variation 
necessary is in the manner of locating the piece and 
in little details of clamping, and so on. The type 
itself is a common one, the use of which can be 
adapted to numerous kinds of work of similar char¬ 
acter. 

Drill Jig for an Eccentric Bushing.—The eccentric 
bushing shown at A, Figure 127, is used as an ad¬ 
justing bushing for obtaining the correct relation 
between the worm and worm-gear sector of an auto¬ 
mobile steering gear. This piece of work has been 
previously bored and reamed at B, and has been 
faced on the end. The drill jig shown in the illus¬ 
tration is for the purpose of drilling the hole, D, in 
the end of the arm as indicated in the illustration. 
The body of the jig is provided with feet, K, on 


CLOSED JIGS 


279 



i 

i 

i 

1 

i 

i 

Ul 

i 

• 

L_ 


_ 

. 

(Tt 

-1—*—r' 

u 

i • / 

/ 

i / 

AJ 


LJ 



JL 


—-K 


PIG. 127. DRILL JIG FOR AN ECCENTRIC BUSHING 




































































































280 


TOOLS AND PATTERNS 


which it rests on the table of the drill press. The 
work is located on a short stud shown at C, and is 
clamped down upon the shoulder of the stud by 
means of the thumb screw, L. This thumb screw 
operates a square plate, M, which bears against the 
top of the bushing at E. The correct location for 
the arm in which the hole is to be drilled is assured 
by means of the thumb screw, F, which acts as a stop 
for the end of the lever, and also by the screw, G, 
which forces the work over against the screw pre¬ 
viously mentioned. A suitable bushing is provided 
at D, which is so arranged that it can be removed 
and replaced by another bushing of suitable size for 
the reamer. 

The method used in drilling and reaming a piece 
of work in a jig of this kind, is first to drill the 
work, using the drill-sized bushing, and immediately 
after this operation to remove the bushing and sub¬ 
stitute a larger one of the proper size for the reamer. 
This reaming of the hole sizes it correctly to the 
given diameter and produces a smoothly finished 
piece of work. 

The slip bushing shown in this illustration is one 
of many types which can be used when it is neces¬ 
sary to remove one bushing and replace it by another, 
as in reaming a hole after it has been drilled. There 
is very little difference in the types of bushings, the 
essential point in design being that the bushing shall 
be so made that it can be easily and quickly re¬ 
moved and secured firmly when in position. 

Drill Jig for a Radius Bracket.—A somewhat odd¬ 
shaped piece of work which requires a rather pecu- 


CLOSED JIGS 


281 



FIG. 128. DRILL JIG FOR A RADIUS BRACKET 


liar type of jig is shown in Figure 128. The work, A, 
has been previously machined on the surfaces, B 
and C, to the angle indicated. It is necessary, there¬ 
fore, to locate it by the previously finished surfaces, 
and also to provide an end location and clamp the 
work securely in position in the jig. The end loca¬ 
tion is assured by means of the stop screw, E, and 
by the thumb screw, F. This thumb screw, F, is 
hand operated after the work has been thrown over 






































































282 


TOOLS AND PATTERNS 


into the position shown, by means of the screw, K, at 
the other end of the jig. 

The work to be done in this operation is the drilling 
of the hole, D, through the angular side of the piece, 
and also two other holes indicated at R. Suitable 
bushings are provided for all of these holes, as can 
be clearly seen in the illustration. The bushing used 
for the hole, D, is of the slip variety and is indi¬ 
cated at G. On the opposite side of the jig a bush¬ 
ing, H, is located for a counterbore which is used 
in one side of the hole ; D. In operation the work is 
placed in the jig until the surface, B, rests against 
the angular part of the jig, after which the set screw, 
K, is used to move the work forward in the jig 
until it strikes the set screw, E. The thumb screw, 
F, is then brought up to make a contact and to 
assist in supporting the work, and the screw, N, is 
used to bring up the angular shoe shown at L, 
against the angular side of the work. The work 
itself rests on the set screws, 0 and P, and is clamped 
down by the screw at M. It will be seen that the 
position of the screw, K, is such that it tends to 
throw the work down against the stop and over 
against the two set screws, E and F. A jig of this 
kind is provided with feet on the sides opposite to 
all points which are to be drilled, so that the jig 
will have a firm foundation on which pressure can 
be brought to bear. 

In drilling the piece shown, the slip bushing, G, 
is first used, and a large hole is drilled through the 
portion, D. After this the bushing is removed, and a 
counterbore of special shape is fed down through the 


CLOSED JIGS 


283 


liner bushing indicated. The jig is then turned over 
and the process is repeated through the bushing, H. 
In like manner the other holes are drilled by spindles 
in a multiple-spindle drilling machine, these spindles 
being arranged in proper location to give the correct 
spacing for the various holes. Jigs of this character 
are used for many kinds of work and can be adapted 
to suit different conditions. 

Drill Jig for a Crooked Lever.—The work shown 
at A, Figure 129, is a crooked lever, both ends of 
which are to be drilled and reamed as shown at B 
and C. In addition to these two holes, there is a 
smaller hole at F, which is to be drilled in the same 
setting of the work. For this operation the lever is 
placed in the jig through the open side and rests 
on the finished pad at each end. At the large end, 
the flat surface of the work rests on a fixed support, 
as indicated, but at the smaller end, B, the support is 
assured by means of the screw bushing shown at H. 
After the work has been placed in position, this 
screw bushing is jacked up by means of a pin placed 
in the holes shown at 0. 

The location of the work is gained by the Y-blocks 
at E. It will be noted that the Y-block at this end 
of the lever is fixed, but at the other end there is 
a floating member attached to the thumb screw, L, 
which also acts as a Y-block locater. This is clearly 
shown in the upper view. After the work has been 
placed in position and located as mentioned, the 
thumb screw, D, is turned down firmly against the 
web of the lever. The work is now in position to 
be drilled, and the jig is turned over on the legs 


284 


TOOLS AND PATTERNS 



FIG. 129. DRILL JIG FOR A CROOKED LEVER 


shown at P and K for the various drilling operations 
involved. 

The principles involved in this jig are identical 
with those which can be applied to many other 
varieties of lever jigs. Naturally it is always neces¬ 
sary to adapt any jig to the work on which it is to 
be used, but the principles underlying the design 
of jigs of this kind are much the same, and suitable 
adaptations can be made for various conditions of 
work in the shop. 

Large Trunnion Jig.—When the work to be 
handled is of large size and somewhat awkward in 
shape, it is sometimes desirable to hold it in some 













































CLOSED JIGS 


285 


sort of jig which can be easily loaded. After the 
piece has been placed in the jig, the entire mechanism 
can be turned over by means of a crank or other 
mechanical device, so that it will lie in the correct 
position under the drill-press spindles. Furthermore, 
a jig of this kind should be arranged so that several 
sides of the work can be drilled without removing 
the piece from the jig and without any necessity 
for more than one operation of clamping. A suit¬ 
able indexing device can be made, so that the accu¬ 
racy of the holes which are to be put in from differ¬ 
ent sides of the work can be assured without diffi¬ 
culty. 

A jig of the kind mentioned is generally termed a 
trunnion jig. The possibilities of a trunnion jig are 
dependent on the number of sides of the work which 
are to be drilled. When the work is such that it 
must be drilled from four or five directions, it is 
possible to make a double trunnion jig which can be 
indexed in several directions to provide for the drill¬ 
ing of holes from several different angles. However, 
a jig of this kind is more or less complicated, and it 
does not always prove a profitable investment to 
make one unless the work is in sufficient quantity 
so that the expense incurred will be offset by the 
saving in the manufacturing time. Nevertheless, drill 
jigs of the trunnion type having a suitable bearing 
on which they can be swung, are more or less 
common. 

An example of a trunnion jig of this kind is shown 
in Figure 130. The work, A, in this case is a trans¬ 
mission-case casting made of aluminum and pre- 


286 


TOOLS AND PATTERNS 



FIG. 130 . EXAMPLE OF TRUNNION JIG FOR A TRANSMISSION 
CASE COVER 


viously machined along the surface, C. It has also 
been drilled at two points for dowels, as indicated 
at B, and these holes are used as locating holes for 
the work when the piece is being drilled. In locat¬ 
ing the piece, A, in the jig, the position of the 
entire jig is as indicated in the illustration. The 
work is placed in the U-shaped casting, H, locating 
on the dowel pins at B. After it has been placed in 
position the latch, F, is swung down into position 
and the thumb screw, G, is tightened to secure the 
latch. After this the two thumb screws shown at D 
and E are tightened to make the work absolutely 
secure in the jig. 

The piece is now ready to be drilled, but it will be 
noted that the holes, J, which are to be drilled are in 
the under side of the work. The entire unit, H, is 
hung on two bearings at S, and these bearings are 
situated in the carriage, L, which is furnished with 
wheels, N, traveling along a track located on the 
bed of the drill press, An enlarged section of the 




















CLOSED JIGS 


287 


track is shown at P-Q, which makes the construc¬ 
tion of this part of the jig clearly apparent. The 
purpose of the track is to provide a means of mov¬ 
ing the jig from one machine to another when one 
part of the work has been drilled by a series of 
spindles and another set of holes is to be handled on 
another machine. 

When the jig is to be indexed preparatory to drill¬ 
ing, the pull pin, K, is removed from the bushed hole 
indicated, after which the handle, L, is operated, 
thus indexing the entire jig by means of the gears 
shown at M. This indexing operation turns the 
entire jig over, so that it is in the correct position for 
drilling the work. 

An arrangement of this kind will show very 
satisfactory results when a high production is to 
be obtained on a given piece of work and when the 
piece is of such size and shape that it can not be 
conveniently handled in a single operation. By ar¬ 
ranging a track like the one indicated in the figure, 
and by suitably fastening this track on cradle cast¬ 
ings, like those shown at B, the round shaft, 0, makes 
an excellent track used in connection with the 
grooved wheels. It is entirely possible, with an ar¬ 
rangement of this kind, to set up two or three ma¬ 
chines with properly-spaced spindles so that the jig 
can be rolled from one machine to the other with 
very little loss of time and without the necessity for 
more than one setting of the work. 

In this chapter an attempt has been made to de¬ 
scribe a variety of drill jigs which are in common 
use, but it is eivdent that it is entirely out of the ques- 


288 


TOOLS AND PATTERNS 


tion, in a work of this kind, to go into every matter 
of design in great detail. Enough examples have 
been given, however, to make the subject as clear 
as the space will permit and the examples given have 
been selected with a view toward simplicity and 
variety. 


CHAPTER XIX 


LUBRICATION OF CUTTING TOOLS 

Necessity of Lubrication.—If a man has an auto¬ 
mobile, a bicycle, or some other piece of machinery 
and wishes the machine to be at its best, the first 
thing that he considers is the proper lubrication of 
the various bearings so that the mechanism will run 
as smoothly as possible. Now, in cutting any piece 
of metal the question of lubrication also arises, for 
as the cutting tool is in constant contact with the 
metal which is being cut, it is obvious that a great 
deal of friction is produced. The friction heats the 
tool, and if the amount of heat generated is excessive, 
the result will be disastrous to the cutting tool and 
eventually result in its ruin. It is necessary there¬ 
fore on some kinds of material to provide a suitable 
cutting lubricant in order to carry away the heat 
generated by the friction of the tool and to make 
the work easier. Certain kinds of material do not 
require lubrication, but on others it can be used to 
great advantage. 

The question of lubricating a cutting tool is of so 
great importance that it must be thoroughly consid¬ 
ered. A great many points come up in connection 
with cutting lubricants for different classes of mate¬ 
rials. It is out of the question to attempt to prescribe 
289 


290 


TOOLS AND PATTERNS 


a cutting lubricant which will be suited to any par¬ 
ticular kind of metal without knowing the exact 
nature of the alloy of which the metal is composed. 
Let us suppose that some one were to ask the question, 
“What is the best cutting lubricant for aluminum?” 
It would be difficult to answer this question abso¬ 
lutely without knowing of what alloy of aluminum 
the casting was composed. 

This reminds me of an anecdote which I once heard 
of two Englishmen who were in this country for the 
first time and who were talking about the peculiar¬ 
ities of Americans in general. The two men were in 
a railroad station at the time, and one remarked to 
the other, “They say that an American always an¬ 
swers a question by asking another one.” “That 
seems very improbable,” replied the second. “Well, 
let us see if this is really the case. I’ll try it now.” 
So he strolled over to the ticket office and asked the 
ticket agent, “I want a ticket. How much is it?” 
And the agent replied, “Where to?” 

So in the matter of cutting lubricants for different 
materials, if I were asked to state the type or kind 
of lubricant best suited to a given material, I would 
have to ask what the composition of the casting 
was before it would be possible to name the proper 
kind of lubricant to use on the work. 

There is considerable difference of opinion among 
manufacturers as to what particular lubricant is bet¬ 
ter for certain classes of work. However, a variety 
of lubricants have been proved to give excellent 
results, and although the proportions of their com¬ 
ponent parts may vary somewhat, the ingredients 


LUBRICATION OF CUTTING TOOLS 291 

themselves are very similar. In this chapter we will 
describe a number of lubricants which have been used 
with success on different kinds of materials. Although 
modifications of the formulas herein given may be 
found advisable in some cases, the ones given are 
thoroughly practicable for commercial purposes. 

Composition of Cutting Lubricants.—In the first 
place it must be remembered that all materials do 
not require lubrication. Cast iron, for example, is 
not lubricated to any extent. (Some manufacturers 
have attempted to use various lubricants on cast 
iron, but I do not believe that the results obtained 
have been at all convincing. At any rate, cast iron 
is generally cut dry.) Brass is usually cut dry. 
Aluminum is sometimes cut dry and at other times 
it is cut with a lubricant. 

We have decided that the purpose of a cutting 
lubricant is twofold, one of the purposes being the 
lubricating of the cutting tool, thereby eliminating 
the friction to a certain extent, and the other is a 
cooling action intended to keep the cutting tool in 
such condition that it will not be ruined by too 
great heat. Now, in discussing the kinds of lubri¬ 
cants used for these purposes, we can consider that 
practically only two kinds of lubricants are in use. 
One of these is composed of lard oil or mineral oil, 
or of mixtures of mineral and lard oil. The other 
compound is of a soapy nature and was devised in 
order to provide a greater cooling effect than that 
obtained by the use of oil only , at the same time it 
carries sufficient grease so that it provides a certain 
amount of lubrication also. 


292 


TOOLS AND PATTERNS 


A solution of sodawater was formerly used as a 
cooling medium, but as this compound possesses 
little lubricating action it has been gradually re¬ 
placed by other compositions carrying greater per¬ 
centages of grease. A number of solutions are on 
the market at present, and most of these are in the 
nature of emulsions. A saponaceous, or soapy, fluid 
is formed by means of potash, or soda, added to 
animal oil which is readily soluble in water. In 
mixing a compound of this kind it is only necessary 
to dissolve soap in mineral oil and then add water 
sufficient for the purpose in hand. 

It is important in mixing a solution of cooling or 
cutting compounds for any kind of work to make 
sure that the action of the compound is not such that 
it will cut away the lubricating oil used in the bear¬ 
ings of the machine. Unless care is used in making 
a proper mixture, there is some danger of obtaining 
so “sharp” a mixture that it will eventually remove 
all the lubricating oil from whatever portion of the 
machine it touches, and the natural result will be 
that the machine itself will be seriously injured 
through friction. 

The different compositions of cutting lubricants 
as used by various manufacturers are much the 
same, although their method of mixing and the 
various proportions of the ingredients may differ 
somewhat. In general, the following formulas will be 
found to give good results, although the mixing of 
the compound may vary according to the amount of 
water which is used. 

Bar stock or machine-steel forgings can best be 


LUBRICATION OF CUTTING TOOLS 293 

cut with a mixture of lard oil, borax, and water, or 
lard oil or mineral oil can be used alone. 

Steel castings, and bronze or malleable iron can be 
cut to advantage with a lubricant composed of min¬ 
eral oil alone. 

A mixture made of half lard oil and half kerosene 
will prove the best for aluminum castings, and pro¬ 
duces a very smooth cutting action that is much 
better than kerosene alone. Kerosene alone is advo¬ 
cated by many manufacturers, but it is not equal to 
the lubricant mentioned. 

Wide-faced and forming tools seem to give better 
results when lard oil alone is used with them, and 
tools that are made of carbon steel seem to have 
longer life with this lubricant. 

Lubricating Compound for Steel.—An excellent 
borax compound for steel is made as follows: Dis¬ 
solve one pound of borax in seven gallons of hot 
water and allow the mixture to cool. After it has 
cooled, add to it one gallon of lard oil thoroughly 
mixed. Enough borax should be used to make the 
oil and water mix thoroughly. The quality of the 
lard oil used will affect the amount of borax, and 
hard or soft water will also make a difference in the 
proportions. The quantities mentioned are safe to 
start with, although slight variations may be needed 
to suit particular cases. 

A convenient method of mixing cutting lubricants 
of this kind is to use forty gallons of hot water to 
seven pounds of borax, mixing the solution in a fifty- 
gallon barrel. When the solution has cooled, seven 
gallons of lard oil can be stirred in, after which it is 


294 


TOOLS AND PATTERNS 


ready for use. As previously mentioned, the greatest 
care should be used in the amount of borax, because 
too much borax has a tendency to cut away the 
lubricating oil used on the machine, so that trouble 
may be caused from imperfect lubrication of the 
machine parts. In general, however, it will be found 
that a tool will wear away more quickly when borax 
solution is used than if pure lard oil is used, but the 
cooling action on the tool is considerably greater 
with the borax water. 

Cooling by Lubrication.—The matter of cooling 

the tool and lubricating it at the same time is of so 
much importance that it is well to speak at this time 
of the particular necessity for proper lubrication 
when heavy cuts are being taken. As an example, let 
us consider that a piece of steel is being cut with a 
heavy feed and at about the maximum speed, and 
it is desired to select a suitable lubricant for it. As 
the friction produced by a heavy cut is so much 
greater than if the cut were to be a light one, it is 
apparent that in order to produce as good a lubricat¬ 
ing effect as possible it will be necessary to use an 
oil rather than a borax compound. But if the same 
piece of steel is being machined at high speed and 
the amount of stock which is being removed is not 
very great, the heating of the tool will be very much 
greater, and a borax solution will therefore be found 
to give better results. 

Another factor that is worthy of comment in re¬ 
gard to the use of cutting lubricants on machine 
tools, is the matter of power consumption. Author¬ 
itative data on this subject is difficult to obtain, but 


LUBRICATION OF CUTTING TOOLS 295 

as it is known that a machine will run easier with 
oil in the hearings, I am firmly convinced that a cut¬ 
ting tool will remove metal easier if it is properly 
lubricated. Experiments that have been made along 
these lines have been widely different in the results 
obtained, and to my knowledge no absolute tests 
under careful management have been made that give 
contradictory data. 

Lubricating Stream to Remove Chips.—Another 
function which should be mentioned is the use of 
a stream of cutting compounds to wash away the 
chips that are generated by the tool. This item is 
more serious in some cases than in others. For ex¬ 
ample, take the drilling of a deep hole in a piece of 
steel: Here, at times, it is difficult to get the chips 
that are being rapidly removed out of the way, and 
they stick in the flutes of a drill or pack around a 
cutting tool in such a way as to interfere greatly 
with the proper machining of the piece. 

Let us take as an example a piece of steel which 
is being drilled on a horizontal turret lathe. Refer¬ 
ring to Figure 131, the work, A, is held in a special 
collet chuck as shown in the illustration. The turret 
lathe in this case is provided with a system for 
lubricating the tool through a pipe, B, which con¬ 
nects with the turret as it is indexed from one posi¬ 
tion to the other. The drill, C, is of the “oil type, 
that is, it has a hole through the center and two 
ducts which lead out directly at the point of the 
drill through which the cutting lubricant is forced 
by means of the pump on the machine. As the pump 
forces the lubricant to the drill, the high pressure 


296 


TOOLS AND PATTEENS 



FIG. 131. INTERNAL OILING ARRANGEMENT FOR DRILLING 
ON A HORIZONTAL TURRET LATHE 


of the fluid tends to force out the chips as they are 
generated by the end of the drill, along the flutes, so 
that eventually they find their way to the end of the 
work and drop out. A method of forcing lubricants 
through tools used on the turret lathe is not uncom¬ 
mon, although the practice varies somewhat with 
different manufacturers. Boring bars are not as 
easy to lubricate as some other forms of cutting 
tools. 

Lubricating Through the Spindle of a Turret 
Lathe. —The device shown in Figure 132 was applied 
to a horizontal turret lathe in order to provide proper 
lubricating facilities for the cutting tools used in the 
inside work on the piece, A. The device was applied 
from the rear end of the spindle, but the pump used 
to force the lubricant to the spindle was a component 
































LUBRICATION OF CUTTING TOOLS 


297 



FIG. 132. LUBRICATION OF SPECIAL NATURE APPLIED TO A 
TURRET LATHE 


part of the machine. A reference to the illustration 
will make it apparent that a boring bar, B, is used 
to bore two diameters on the inside of the work, and 
is piloted by a bushing, C, in the chuck. 

In order to provide the inside cutting tools with 
proper lubrication, a pipe, D, is connected to the 
lubricant supply pump and is passed through the 
end of the spindle where it is guided in the packing 
bushings. Through the spindle and at the forward 
end, E, it is provided with a telescoping tube of 
smaller size, as shown at F. This smaller tube 
reaches forward and enters a hole in the end of the 
boring bar. From this hole other smaller holes lead 
out directly in front of the cutting tools. A coil 
spring takes care of the variations as the bar,. B, 
progresses into the hole during the cutting action, 
and a stop collar, G, limits the forward movement 
of the tube, F, as it strikes against the end of the 
boring bar. 

The application of a device of this kind to a turret 
lathe is not costly, and the results obtained by its 























298 


TOOLS AND PATTERNS 


use are very satisfactory. At different times I have 
made a number of equipments for oiling tools through 
the spindle, most of which have been on a similar 
order to the one shown in this illustration. It is 
obvious that different conditions require slightly 
different methods of handling, but the principles in¬ 
volved in the design are much the same in all 
cases. 

Flood Lubrication. —Nearly every machine of a 
manufacturing type is provided with lubricating 
devices of one kind or another, according to the type 
of machine and the nature of the work to be done. 
A turret lathe of the horizontal variety, for instance, 
is usually equipped with outside lubricating devices 
which will direct a copious supply of fluid against a 
piece of work that is being machined. A milling 
machine is also provided with an outside supply 
system for furnishing cutting lubricants to the cut¬ 
ters and the work, and flood lubrication (which 
means an excess supply of lubricants) is the usual 
method. The production of work from machines 
which are provided with flood lubrication for the 
cutting tools is far in advance of that obtained from 
machines of the older type which had an inadequate 
supply of lubricant. 

In order to supply a machine with a proper amount 
of lubricant, or cutting fluid, and to direct the stream 
or streams to the proper position, it is necessary to 
arrange the piping in such a way that the spouts 
can be swung in any direction, longitudinally and 
vertically. By referring to Figure 133 an excellent 
example may be seen of the application of a cutting 


LUBRICATION OF CUTTING TOOLS 299 



FIG. 133. CUTTING-LUBRICANT SYSTEM ON A BULLARD VERTICAL 

TURRET LATHE 














































300 TOOLS AND PATTERNS 

lubricant system to a vertical turret lathe. This 
system is used by the Bullard Machine Tool Co. on 
their vertical boring mills and vertical turret lathes. 
A standpipe at one side of the machine contains two 
sliding tubes which can be adjusted vertically to suit 
the height of the piece that is being machined. These 
two tubes have spouts, A and B, and suitable cocks, 
as shown at C, to cut off the lubricant or reduce the 
flow. It will be seen that the fluid can be directed 
immediately onto the work, D, without difficulty. 

One of the nice features of the device shown lies in 
the fact that the supply of lubricant is copious and 
can flood the work with a suitable cutting compound 
forced through the pipe by a pump located on the 
machine. After the cutting fluid has been used, it 
flows downwards and finds its way eventually through 
a fine screen back to the pump and is immediately 
sent forth again through the same channel to the 
work. 



CHAPTER XX 


CUTTING FEEDS AND SPEEDS 

A Careful Study Required. —In order to obtain 
maximum efficiency from any machine tool it is an 
essential point that the proper cutting feeds and 
speeds should be used. The question then arises as 
to what cutting speed is correct for any given kind 
of material with a given feed. It is evident that a 
very little difference in the cutting speed and a 
slight variation in the feed used on a piece of work 
will make considerable difference in the number of 
pieces of work that may be produced in one hour, 
one day, or one year. 

Let us suppose that a certain piece of work is 
being machined, and that the feed and speed are a 
little less than they should be. If it takes an oper¬ 
ator ten minutes to produce a piece of work at the 
feed and speed that is being used, then a reduction 
of one minute in the time necessary to machine the 
piece would mean a considerable saving in total pro¬ 
duction time. In order, then, that the maximum 
production should be obtained from any machine, it 
is evident that the cutting feed and speed should be 
very carefully studied. 

Definition of Cutting Speed.— The term “ cutting 
speed in feet per minute” is not always thoroughly 

301 


302 


TOOLS AND PATTERNS 


understood by the non-technical man. In order there¬ 
fore to make the matter more clearly evident to the 
reader a short explanation will suffice. Considered 
in elementary form, cutting speed means the number 
of feet of metal, considered as a continuous strip, 
which passes a given point upon the edge of a cut¬ 
ting tool in one minute. For example: Let it be 
supposed that I am planing a piece of cast iron 5 feet 
long, and that it takes me 10 seconds, or one-sixth of 
a minute, to make a cut the length of the work. It 
is evident that the cutting speed which I am using 
is 30 feet per minute, because it takes one-sixth of 
a minute for 5 feet to pass the cutting tool, and six- 
sixths of a minute will elapse while 30 feet of metal 
are passing the tool, not considering the return 
stroke of the planer. 

In the same way a piece of cylindrical work which 
is revolving and passing a given point on the cutting 
tool, can be considered as a ribbon of metal unwind¬ 
ing from the outside of the work as fast as it passes 
the tool. In this case the circumference must be 
considered in determining the cutting speed. Let us 
assume that I have a piece of cast iron 20 inches in 
diameter which is running at a rate of 10 revolutions 
per minute, and I wish to know at what speed I am 
cutting the work, and whether it should be decreased 
or increased, and how much. 

Formula for Determining Cutting Speeds.—It is 
evident that the circumference of the work, multi¬ 
plied by the number of revolutions per minute at 
which it is running, and divided by 12 (which is 
the number of inches in one foot) should equal the 



CUTTING FEEDS AND SPEEDS 


303 


number of feet per minute at which the work is 
being cut. Or the solution of the problem would 
appear as follows: 


20 x 3.1416 x 10 
12 


= 52.4 ft. per min. 


As this process is a rather tedious one, let us take 
an approximation of the necessary figures, and from 
them derive a formula. If we take the constant, 3.1416, 
and divide it by 12, which is the number of inches 
to the foot, we obtain the figure 0.262, or, in round 
numbers, 0.250. Then by substituting this figure, 
0.250 (or *4), we obtain in place of the solution of 
the problem given above, another one: 

20 x 0.250 x 10 = 20 x ~ — 50 


While this is not exactly correct, it is near enough 
for all practical purposes. 

If we resolve the matter into a formula, then, we 
obtain the following: 


Where 

D = diameter of work. 

N = number of revolutions per minute. 

C = cutting speed in feet per minute. 

If we reverse this process in order to find the 
necessary number of revolutions per minute required 
for a piece of work of a given diameter to obtain a 
given cutting speed, we use the formula 


D 




304 


TOOLS AND PATTERNS 


Taking tlie same example as given above with the 
work diameter, D = 20; cutting speed desired, C = 
50 feet per minute, then 


It will be found that most of these formulas are 
very simple and can easily be memorized, so that 
all cutting speeds for any given diameter can be de¬ 
termined very rapidly by mental calculation. 

The number of revolutions required to obtain cut¬ 
ting speeds for given diameters can be found in any 
mechanical handbook, but such a book is not always 
conveniently at hand when it is desired to know 
what a cutting speed is for a certain class of work. 
In such cases the above formulas will be found of 
great assistance. 

Relation of Speed to Feed.—There are certain well- 
defined rules which can be applied to the correct set¬ 
ting of a feed and speed for a given piece of work 
when the composition and the quality of the work are 
known. An important factor in production work is 
the depth of the cut to be taken on the work. If a 
large amount of material is to be removed and if, there¬ 
fore, the depth of the cut is considerable, it is evi¬ 
dent that the amount of pressure brought to bear 
upon the tool and the amount of power required to 
pull the tool through the work are of first impor¬ 
tance. 

Speaking generally, the depth of the cut has a 
powerful effect on the feed which can be used and 
also on the speed. It would seem that there should 



CUTTING FEEDS AND SPEEDS 305 

be, then, a direct relation between the cutting speed 
and the feed. That is to say, if a speed of fifty feet 
per minute were to be used and a feed of 1/32 of 
an inch per revolution of the work with a depth of 
cut of Ys of an inch, it would appear logical that if 
the cutting speed were to be changed, the amount of 
feed would need to be changed also. Just how much 
change a variation of ten or fifteen per cent in the 
cutting speed would be required in the feed in order 
to produce the same results with the same amount of 
damage or injury to the tool, is a difficult question 
to decide. 

However, the amount of stock to be removed from 
a casting or a forging is, in the majority of cases, 
very nearly uniform when the work is to be put 
through the shop on an interchangeable basis. We 
shall assume in our discussion of cutting feeds and 
speeds, then, that the amount of stock to be removed 
from any given piece of work is according to the 
usual practice. Speaking generally, the larger a 
piece of work is, the more stock is left to be re¬ 
moved by the cutting tool, because on large work, 
variations in the casting are more likely to be found. 

On a piece of cast iron, six inches in diameter, the 
ordinary amount of finish left on the casting would 
not be apt to exceed % of an inch on a side. On 
work 30 inches or more in diameter, there might 
easily be from % to % of an inch of stock to be 
removed. It is very apparent, then, that in ma- 
machining large work the depth of the cut would 
need to be deeper and, therefore, the feed would 
not be apt to be so great. 


306 


TOOLS AND PATTERNS 


But there are other factors which enter into the 
machining of any piece, and these factors sometimes 
seem to contradict themselves. In the machining of 
a large casting, 30 inches or more in diameter, with 
a depth of cut % of an inch, it might he entirely 
possible to take a feed even a little greater than 
would be possible on a small piece six inches in 
diameter. The factors which would influence this 
matter are the power of the machine, the weight 
and rigidity of the work which is being machined, 
and the sectional area of the tool which is doing the 
work. The area of the tool would be proportionately 
greater on a heavy and large machine than on a 
small machine. 

Conservative Cutting Speeds.—It will be noted 

from the foregoing statement that the amount of feed 
and speed which can be used on a given piece of 
work is not by any means an absolutely fixed amount. 
Given, however, a comparatively uniform amount of 
stock to remove from a casting of a known degree 
of hardness, there are certain conservative feeds and 
speeds which can be used with safety. It is always 
necessary in making an estimate of production on a 
given piece of work, to assume a certain cutting feed 
and speed which has been found by long experience 
to be within the limit of safety. 

Assuming that the metals to be cut have been 
pickled or sand-blasted to remove any injurious 
scale that may be upon them prior to the machin¬ 
ing operaton, and further assuming that the amount 
of stock to be removed is not excessive, the follow¬ 
ing table of cutting speeds for different materials 



CUTTING FEEDS AND SPEEDS 307 

will be found to give results well within the limit of 
safety. It is always well in making an estimate of 
production on a given piece of work, to assume that 
the work is normal and not very hard, and that it 
has no excessive material to remove. Under these 
circumstances, after an estimate of production has 
been made, it is easily possible to speed up a ma¬ 
chine slightly in order to gain a little in production, 
providing the material which is being cut proves to 
be of such a quality that it permits a little higher 
speed than normal. 

Cast iron—50 feet per minute. 

Cast steel—60 feet per minute. 

Malleable iron—70 feet per minute. 

Machine steel forgings (15 to 20 point carbon)—65 feet 
per minute. 

Machine steel (black stock)—70 feet per minute. 

Tool steel forgings—35 to 40 feet per minute. 

Steel alloys (containing nickel and chromium)—30 to 50 
feet per minute (depending on alloy). 

Yellow brass—200 feet per minute. 

Composition brass—120 to 150 feet per minute. 

Bronzes— 30 to 80 feet per minute (depending on alloy). 

Importance of Proper Speeds and Feeds. The im¬ 
portance of a correct cutting speed and feed cannot 
be overestimated. It is safe to say that the average 
manufacturer loses more money in the course of a 
year by incorrect setting of speeds and feeds m his 
factory than by any other single item in his total 

outlay. . , , 

A number of reasons are responsible for this, but 
probably the most usual one is the fact that no work- 


308 


TOOLS AND PATTERNS 


man likes to grind tools. If a workman has a num¬ 
ber of pieces of work to do on a machine which re¬ 
quires rather careful i ‘setting up,” he is quite apt 
to run his machine a little too slowly so that it will 
not be necessary for him to grind the tools very 
often. 

It is the duty of any foreman of a department 
in a factory, to make sure that the production time 
on the work in process is as great as the nature of 
the work will permit. It is furthermore the duty 
of the progressive executive to make certain in his 
own factory that he is obtaining the results that he 
should obtain by making a personal examination 
of the methods in use from time to time, and to keep 
himself posted in regard to the work, so that produc¬ 
tive inefficiency shall not be laid to a lack of knowl¬ 
edge on his part. 

Allowance for Exceptional Cases.—While it is all 

very nice for a tool engineer, an executive, or a fore¬ 
man in a factory to determine positively beforehand 
exactly at what speed any piece of work must be 
run, it is an entirely different proposition to tell the 
man in the factory who is doing the work that 
he. must run that work at exactly the prescribed 
speed and feed. Getting back to first principles, it 
would be entirely possible to fix absolutely every 
cutting speed and feed in the factory, providing the 
material which was being cut were exactly of the 
same quality in each and every case. Unfortunately, 
however, foundry practice is not such as to give abso¬ 
lutely certain results. Sometimes a group of castings 
will be found very hard, while in other cases they will 


CUTTING FEEDS AND SPEEDS 


309 


be soft. It is evident that the first group cannot be 
machined as rapidly as the second. 

In these days of rapid production and high speed, 
it frequently happens that several patterns are made 
of the same piece of work, and in order to obtain 
the castings as rapidly as possible, the patterns are 
sent to different foundries. Invariably the castings 
from one foundry will differ in some respect from 
those of another foundry, and due allowance in set¬ 
ting speeds and feeds must be made for such condi¬ 
tions. So also in the case of alloy steels, a very great 
difference may be found in two lots of forgings, al¬ 
though in this case the trouble is not caused by the 
composition as a general rule, but is more likely to 
be the result of an improper treatment of the forg¬ 
ings after they have been made. 

The remedy for conditions of this kind is apparent. 
It is certainly not the part of economy for the manu¬ 
facturer to reduce his production speed just because a 
foundryman or a drop-forge department has made 
errors, or has neglected to do some of the things that 
should have been done before the castings or forgings 
were delivered. However, it may happen that the 
manufacturer does not feel disposed to send back a lot 
of imperfect or improperly treated castings or forg¬ 
ings, and prefers to machine them as they are. In 
such a case he will have to establish arbitrary ma¬ 
chining speeds, and his decisions must be governed 
by the conditions. 

Effect of Lubricant on Feed and Speed.—In the 

previous chapter the matter of cutting lubricants 
was discussed and various data were given in regard 


310 


TOOLS AND PATTERNS 


to the most suitable lubricant for various classes of 
materials. In tool-room work, however, it is very 
often the case that the workman does not wish to 
use a lubricant in cutting a piece of metal. This 
is largely because the use of a lubricant results in 
much dirtier work, which is difficult to handle. Hence, 
the toolmaker prefers to cut his work dry as a gen¬ 
eral thing. There is no particular reason why a 
workman on this class of work should not use his 
own judgment as to lubricants. He might be able 
to produce some classes of work more rapidly by 
using them, because he could use a little higher speed 
and a little more feed, but in the long run no par¬ 
ticular gain would be found. Of course, in making 
heavy roughing cuts in the tool room, or anywhere 
else in the factory, a lubricant will undoubtedly be 
found of great advantage. In the table given pre¬ 
viously in this chapter, it is assumed that a proper 
lubricant is to be used on work which needs lubrica¬ 
tion. 

General Rules.—Speaking generally, the amount of 
feed and speed to be used for any work produced 
in quantities, should be as great as the work will 
permit without obliging the workman to re-grind his 
tool more than three times in one day. Naturally, 
there are exceptions to this rule, but as a general 
thing if the workman is not obliged to grind his tool 
oftener than once a day, he is losing time in produc¬ 
tion. But, on the other hand, if the workman finds it 
necessary to re-grind his tool about once every hour, 
it is a sure indication that the speed is too rapid or 
the feed is too deep. 


CUTTING FEEDS AND SPEEDS 311 

I recall a rather peculiar incident connected with 
the use of the proper cutting speed and feed that hap¬ 
pened some years ago. In passing through a factory, 
a workman stopped me and asked if I could tell him 
what kind of steel he could use in place of the tool 
he then had. On questioning the man it appeared 
that he was grinding the tool after he had produced 
about two pieces, and this tool grinding kept him 
busy for some minutes each time. On examining the 
work, I found it to be a piece of bronze about 4 
inches in diameter. The workman proceeded to cut 
one of the pieces while I was standing by his side. I 
noticed that the speed seemed to be excessive, and 
by counting the number of revolutions per minute, I 
saw that he was running the work at something over 
600 feet per minute. As the work was a piece of 
manganese bronze, it is evident that the tool was 
being ruined about as fast as he could re-grind it. 
After he had reduced the speed to about 100 feet 
per minute he had no further difficulty with the tool. 
This example simply illustrates conditions which 
sometimes obtain in a factory on account of the igno¬ 
rance or carelessness of the worker. 

As it is absolutely impossible to set a cutting speed 
or feed for a piece ol work without making a trial 
to see whether the work is hard or soft, it behooves 
every factory manager or executive to see that the 
greatest care is used in making these determinations. 
After the speeds and feeds have been set as nearly 
correct as possible, it is well to make an examination 
to prove that the results show that the work is being 
produced to the best advantage. The foreman should 


312 


TOOLS AND PATTERNS 


test the various machines from time to time in order 
to make sure that the maximum efficiency is being ob¬ 
tained. For, next to proper cutting tools, speeds and 
feeds are of first importance. In order, then, to see 
that the factory is obtaining the maximum output, 
all these various points must be considered, and each 
one must be planned in such a way that there will be 
no loss either from incorrect handling, from improper 
setting of tools, or from incorrect speeds and feeds. 
When all these matters have been looked into by the 
proper men, the executive can feel assured that he is 
obtaining the full capacity of the machine, and when 
he has done this he has approached closely to max¬ 
imum efficiency. 


CHAPTER XXI 


PLANNING AND LAYING OUT WORK 


Business Aspects of Planning— If a man were 
about to build a bouse, bis first step would be to de¬ 
termine wbat kind of bouse be wanted. He would 
devote considerable time in sketching out certain ar¬ 
rangements of rooms, and after be bad determined 
about bow many rooms be wanted and bow much be 
wanted to pay for the house, he would take bis 
sketches to an architect who would draw up a set 
of plans from them. After the architect had planned 
the bouse carefully, he would make an estimate on 
the cost of the various building operations. That is 
to say, be would estimate the amount of excavation 
required for cellar and foundations and the cost of all 
other matters connected with the actual building. 
He would then submit his plans to a number of car¬ 
penters and builders and obtain bids from them.* 

At least, this is the procedure that would be fol¬ 
lowed by the average man; but here and there one 
will find a peculiarly constituted individual who, 
quite probably, would take his rough ideas to a car¬ 
penter and say, “Here are some ideas of a house I 
want built. Go ahead and build it like that. The 
resulting house can readily be imagined. 


* Full discussion of the mechanism of planning will be found in 
Planning and Time Study, by G. S. Armstrong, Vol. 8, Factory Man¬ 
agement Course. 

, 313 



314 


TOOLS AND PATTERNS 


In any kind of business venture involving the out¬ 
lay of a number of dollars, a business man would be 
sure to investigate thoroughly all matters connected 
with the project. In fact, in any buying or selling 
proposition, the man whose money was to be used 
would be apt to look up every point in connection 
with the spending of his money. So also in the manu¬ 
facture of any kind of product, it is of the first im¬ 
portance to study the methods of production that 
are to be used and to plan carefully in advance all 
of the operations necessary to complete the various 
parts for the finished product. 

The importance, then, of the planning department 
in manufacturing can readily be seen. It would cer¬ 
tainly be the height of folly for any manufacturer 
to go ahead and obtain a great number of castings, 
forgings and other material from which the various 
parts were to be manufactured, and then, without 
further thought about the matter, to put these parts 
out into his factory without any particular plan or 
scheme of operation in his mind. And yet in many 
cases, especially in old-established factories, the mat¬ 
ter of planning and laying out the various operations 
for any given piece of work is almost entirely 
neglected. It is true that the operating official, in 
cases of this kind, depends largely upon his foreman 
and workmen to step into the breach and produce a 
finished piece of work which resembles the mechanism 
which he is attempting to build. In the progressive 
factory, however, the planning department receives 
the most careful attention, and the men who are at 
the head of it are specially trained. In addition, their 


PLANNING AND LAYING OUT WORK 


315 


long experience enables them to plan in advance 
every detail of the work to be done. In no other way 
can the greatest efficiency be obtained from any fac¬ 
tory, and although the outlay necessary for a well 
organized planning department is fairly large, the 
results obtained more than offset the expenditure. 

One of the best examples of careful planning can 
be found in the Ford Motor Company plant in De¬ 
troit. Were it not for the care and forethought 
which has been used throughout this factory, it would 
have been impossible to obtain the tremendous pro¬ 
duction of these Ford cars. 

Tool Engineering Methods. —The importance of tool 
engineering has only recently been brought to the at¬ 
tention of the manufacturer. A few years ago the 
tool designer in a factory was supposed to lay out 
the various operations on the work which was to be 
done, but this laying out of operations was in the 
main a rather unfinished procedure. It is true that 
the old-fashioned tool designer would make a rough 
layout of operations necessary to complete a certain 
piece of work, but he would not go into the matter 
very thoroughly. The method used by the modern 
tool engineer, however, is such that every point in 
the manufacture is taken up with the greatest care 
and nothing is left to chance. All the operations 
which are to be done on the work are simply planned 
in accordance with the equipment of the factory. 
More than this, the equipment (if it is insufficient to 
do the work required) is added to, in order that 
maximum efficiency on the work in process may be 
obtained. 


316 


TOOLS AND PATTERNS 


The matter of planning is of such great importance 
that I intend to take it up in this hook in consider¬ 
able detail. I believe that the best way to describe 
the methods used and the processes which are ap¬ 
plied by the tool engineer, is to describe the various 
steps which are taken. In order that the subject may 
be as clear as possible, let us assume that a modern 
factory, very well equipped with machine tools of 
good design—one which has been used for automobile 
work—is about to proceed with the manufacture of 
a new model, and that the drawings of the complete 
mechanism have been handed over to the tool engi¬ 
neer ready for him to design the tools and fixtures 
for the work which is to be done. Let us also assume 
that the tool engineer has been employed by the same 
company for several years, so that he is thoroughly 
familiar with the machine tool equipment. 

Let us follow the steps taken by the tool engineer 
in this work, noting the various points of impor¬ 
tance, which will be discussed at length later in this 
chapter. Let us assume, then, that the tool engineer 
has a pile of blue-prints on his desk—he picks up 
one of the important pieces (usually one of good 
size and considerable importance), and takes up the 
points logically about as follows: 

1. —Looks over each blue-print, compares it with 
the assembly drawing, and notes the important fits, 
the relation of the piece in question to the other 
parts of the mechanism, and so on. 

2. —Makes rough notes of the various operations 
necessary for the completion of the work. 

3. —Looks over the machine-tool equipment of the 


PLANNING AND LAYING OUT WORK 317 


factory, to see wliat machines are best adapted to 
produce the work necessary. 

4. —Determines the jigs and fixtures needed in the 
work of production, notes gauges necessary, and also 
the accuracy required for the various fits. 

5. —Lays out the operation sheet in detail. 

6. —Makes rough pencil sketches of jigs, fixtures 
and other tools necessary in the production. 

7. —Makes layout sheets. 

8. —Makes time-studies from layout sheets. 

9. —Designs jigs, fixtures, and special tools, together 
with gauges needed for the work. 

10. —Notes number of machines required, deter¬ 
mined by the time-studies made for the various oper¬ 
ations. 

11. —Turns over the time-study sheets to the cost 
department, in order that piece-work prices may be 
set from the estimated time of production. 

Now these various steps which are taken by the 
tool engineer are not all undertaken at once, but ap¬ 
proximately in the sequence just given, although the 
practical engineer is often able to combine several 
at a time. Let us now take up each of the points in 
detail. 

1: Preliminary Processes.— Now in the first step 
which the tool engineer takes, he makes a rather rough 
analysis of the work which is to be done, but he does 
try, in this preliminary inspection, to grasp the im¬ 
portant details of the construction and obtain a very 
good general idea of what lies before him. In addi¬ 
tion to this, he familiarizes himself with the general 


318 


TOOLS AND PATTERNS 


points in the construction of the mechanism which 
he is to build, by an inspection of the assembly draw¬ 
ings. He studies these assembly drawings carefully, 
in order to learn the general construction of the en¬ 
tire mechanism of which the piece shown on the blue¬ 
print that he is examining, is a component part. He 
notes very carefully whether certain of the parts 
should be a tight fit, or whether they should be a 
sliding or a running fit, and he determines the im¬ 
portance of their relation to the entire mechanism. 
After the tool engineer has gone over a few pieces 
of work in this way, he begins to form a very good 
idea of the work which he is about to do. He is now 
ready for the second step in the process. 

2: Preliminary Layout of Operation.—Taking up the 
piece now in detail, the tool engineer roughly plans 
the operations which are necessary for the comple¬ 
tion of the work, and makes notes in pencil in the 
form of a memorandum, by which he is guided when 
he makes the more serious, careful planning. For 
example, he makes a note to this effect on his mem¬ 
orandum pad: “This piece must be chucked, the hub 
must be turned, and the inside must be bored out on 
a turret lathe. The other end of the work also must 
be finished and turned, requiring another screw-ma¬ 
chine or a turret-lathe operation. There are to be 
six drilled holes around the flange of the piece, and 
these must be bored in a drill jig on a multiple- 
spindle drilling machine. There are also several 
other operations of milling and counterboring, and 
perhaps even one or two besides these.’’ In any event, 
the tool engineer’s memorandum on this work will 


PLANNING AND LAYING OUT WORK 


319 


cover everything which is to be done to the piece, 
but it may be that the operations, as noted by him, 
may not be in the sequence to produce the piece to 
the best advantage. This matter will be taken up 
later as the careful layout of operations is made. 

3: Machine-Tool Equipment. —Now it must be 
understood that although the points mentioned are 
given in sequence, in reality often, as I have said, 
many of these points are taken up by the tool engi¬ 
neer at the same time, since he is trained to this 
kind of work, and therefore when he thinks of a 
piece of work or an operation which is to be done 
on a given piece of work, his mind automatically 
selects the type of machine which, in his estimation, 
is most suited to the work in hand. He also is pos¬ 
sessed of a knowledge of the various machine tools 
which the factory has on hand, and knows something 
about their condition and their adaptability to cer¬ 
tain classes of work. It is obvious, however, that 
in a large factory the tool engineer cannot carry all 
of these details in his mind, so that it is necessary 
for him to have a complete record of the machine 
tools contained in the factory. 

This matter brings us to the point of a reference 
machine-tool index, which every progressive tool en¬ 
gineer must have. The amount of detail contained 
in a record of this kind is governed by the size, of 
the factory and the kind of product which is being 
manufactured. It is evident that in a small factory 
it would be comparatively unnecessary to have a de¬ 
tailed record of every machine tool in the shop, with 
its feeds, speeds, and other data regarding its capa- 


320 


TOOLS AND PATTERNS 


city. But it will be found that in a large factory 
details of this kind are of the greatest importance. 
For work of this sort, then, the progressive engineer 
in a large factory endeavors to make his index of 
machine tools as complete as possible. I have found 
in my own work of tool engineering, that a large 
card with an outline of the machine tools upon it, 
in at least two views, and with various data con¬ 
cerning feeds, speeds, and capacity, is of the great¬ 
est value. I believe that a card is much better than 
a loose-leaf book, because the card can be taken out 
of the file and used as a reference by the tool de¬ 
signer without disturbing other data which may apply 
to other machines. 

Perhaps a still better scheme would be to have the 
data on the various machines drawn up in such form 
that it can be blue-printed. It is apparent that if a 
blue-print were to be made there would be little 
danger of any cards getting lost and of the conse¬ 
quent large amount of labor to accumulate the in¬ 
formation once more. An example of a machine-tool 
record record card which I have found of great value, 
is shown in Figure 134. It will be seen that this 
card is very complete with respect to the data needed 
by a tool engineer to determine whether or not a 
certain type of machine is suited to the work in hand. 
If this kind of information is lacking, it is necessary, 
in designing a set of tools for any given machine, to 
have the tool designer or a draftsman go into the 
shop and make certain measurements on the machine 
itself, or else obtain what meager information he can 
from a catalogue. 




PLANNING AND LAYING OUT WORK 


321 



FIG. 134. MACHINE TOOL RECORD CARD FOR A TURRET LATHE 
























































































































































322 


TOOLS AND PATTERNS 


Now, assuming that our tool engineer is well 
equipped with data of this kind, he can very easily 
look over the work which is to be done and determine 
which machine of a certain class is best suited to 
the work. He may be aided in this selection by a 
knowledge of the way in which a piece of similar 
character was machined at some previous time, but 
whether this is the case or not, new machine tools 
may have been added since that time which are more 
adaptable to the work. In this case it is natural 
to assume that the tool engineer will select the more 
modern type of machine. Another point which must 
be considered in the same connection, is the location 
of any given machine in the factory. The matter of 
handling a piece and taking it from one department 
to another and then back again, entails an extra 
cost of handling the work, and this should be avoided 
as far as possible. 

4: Jigs, Fixtures, Tools, and Gauges.— Now, the 
tool engineer has reached the point in his analysis 
at which he is ready to take the fourth step. The 
engineer then looks over the blue-prints carefully, 
and notes on his memorandum sheet that he needs 
the following tools: a drill jig, for drilling a certain 
series of holes; a milling fixture, for milling a cer¬ 
tain part of the work; and some turret lathe fixtures, 
for operations of a cylindrical character, such as 
boring or turning of the work. He may also decide 
that some particular piece of work can be handled 
to advantage on an engine lathe, or, if it is large, 
on a vertical boring mill. When the engineer looks 
over these pieces he does not stop to consider design, 


PLANNING AND LAYING OUT WORK 323 

but simply decides that be needs one jig or two jigs 
and one or two milling fixtures, and perhaps a turret 
lathe faceplate, or special sub-jaws, or some other 
types of fixtures. At this time, also, the matter 
of gauging is considered, and a memorandum is made 
as to the types of gauges needed—whether they are 
to be plug, ring, snap, or indicating. Also, whether 
the work is to be gauged from some of the rough 
surfaces in order to make sure that a proper amount 
of finish is left for some subsequent operation, or 
to make sure that there is a clearance between some 
finished portion of another part and a rough portion 
of the work in hand. In connection with this phase, 
he must frequently refer to the assembly drawing 
of the mechanism in order to make sure that all 
these points have been considered. Having gone to 
this point in the analysis, the tool engineer is now 
ready to go into the matter of the operations on the 
work in detail. 

5: Laying Out Operation Sheets. —In connection 
with the preliminary work mentioned, this fifth step 
represents the most important of all the work done 
by the tool engineer. One of the peculiar things 
about the average manufacturer is that when he sees 
an operation sheet completely and properly made out, 
he does not realize for an instant the amount of work 
necessary to produce a result such as that which 
appears on the operation sheet. He sees, for example, 
a sheet perhaps 10x12 inches in size, on which is 
a list of the operations and the tool called for, and 
everything appears to him to be as simple as a, b, c. 
If, however, the executive, in considering the work 




324 TOOLS AND PATTERNS 


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FOUR PIECES PER UNIT 



































































































PLANNING AND LAYING OUT WORK 325 

of the tool engineer in this respect, were to stop for 
a moment and think that every word written on the 
sheet represents the most careful thought, and that 
only as a result of a number of years of hard ex¬ 
perience has the tool engineer acquired the knowledge 
and skill necessary in the laying out of an operation 
sheet—then the executive would acquire a more 
wholesome respect for the tool engineer and for his 
work. It is only recently, as I have said, that the 
executive has been able to see the value of prelimi¬ 
nary planning as carried out and brought to com¬ 
pletion by the experienced tool engineer. Therefore, 
to the executive who has not reached this point, and 
who still seems to consider that this work is more 
or less of a “cut and dried” proposition, I would 
recommend that he reconsider his attitude in this re¬ 
gard and give the tool engineer the credit to which 
he is entitled. 

In the first place, an operation sheet in itself 
should be made in such form that it gives all the 
information necessary in regard to the tool equip¬ 
ment and the machines necessary to do the work. 
I have laid out a number of operation sheets for 
different firms and on various classes of work, and 
I have found that a sheet similar to the one illus¬ 
trated in Figure 135 is about as complete as any¬ 
thing of this kind can be made if the sheet is to be 
of a size to allow of binding in a loose-leaf holder, 
for ready reference. The form indicated is preferably 
about 14 x 17 inches in size, but it can be made a 
trifle smaller if desired. It is bad practice, how¬ 
ever, to endeavor to make a sheet of this kind very 


326 


TOOLS AND PATTERNS 


small, as the necessary information cannot be in¬ 
cluded on a sheet of much smaller size than that 
just mentioned. Referring to the sheet shown in the 
illustration, the reader will see that the data con¬ 
tained on it is complete to the smallest detail. At 
the upper left hand corner a small scale drawing 
of the piece appears, in order that a reference to 
the various operations may be made by means of 
letters, as indicated. Generally the drawing of the 
piece can be made about one-quarter scale, but on 
very large work it may be advisable to leave a 
larger space for the outline drawing. This matter 
is largely determined by the class of work which is 
to be done. I believe that the form shown gives every 
essential detail in regard to any piece of work which 
is to be manufactured, and forms a complete record 
(which can be referred to at a moment’s notice. If 
desired, the operation sheet can be printed on tracing 
paper, and afterward blue-printed so that any num¬ 
ber of record proofs can be made. 

It will be seen that a reference to a sheet of this 
kind will give the executive or the tool engineer 
all the information which he needs, from the process 
used in manufacturing the product, down to and in¬ 
cluding the type of gauge needed and the drawing 
number of the gauge, or of the tool, jig, or fixture. In 
addition to this, the estimated hourly production per 
machine is given in the “Remarks” column, and the 
number of machines which are required for what¬ 
ever production may be determined upon before¬ 
hand. The “Remarks” column also has a little 
additional space, which can be used for any data 


PLANNING AND LAYING OUT WORK 


327 


in addition to that for which space is provided in 
the tabulated list. 

After the tool engineer has gone into the matter of 
machining the work, and has laid out the operations, 
the tool designers use these sheets to work from, 
and as fast as the drawing numbers have been ob¬ 
tained from the clerk, they are entered up in their 
proper place against the tool or fixture which they 
represent—so that before very long, the record is 
complete. When this point has been reached, the 
sheet should be either blue-printed or copied, and 
an original should be filed away in a record book, 
from which no sheet must ever be taken for any pur¬ 
pose whatsoever. If it is found necesary at any 
time, during the progress of the work, to make a 
change in the method of handling, a record of the 
change which is to be made should be filed in a 
separate book devoted entirely to this purpose. A 
statement of the reasons for the change should be 
embodied in the record, and the authority for making 
the change must also be given. It is not an uncom¬ 
mon thing for an operation sheet for a difficult piece 
of work—like a crank case for an automobile, or a 
receiver for a military rifle—to be worth several 
hundred dolars in actual labor expended on the plan¬ 
ning of the operations shown on the sheet. It is 
therefore evident that it behooves any factory execu¬ 
tive to see that the greatest care is taken in regard 
to these points. 

In laying out the operation, the tool engineer goes 
into every detail of manufacture carefully, as will 
be seen if the illustration is referred to. At the 


TOOLS AND PATTERNS 



Third Opera tioh 
4™ Turret Face 
Size - D 


1- Pm Chuck-IReq Dwg.No. Made by PScJ 

2- Rough Turning Tool ■ l-Req Std 

4 - Radius Tool ■ l-Req. Sfd. 

5- False Jaw- 3-Req Dwq.no. 1121 

7- Rough Bonng Tool - I-Req. Dwq Mo. 1003 

6 - Finish Bonng Tool• I-Req. Dwq.Mo 1003 

3- Stzmg Bar- l-Req Dwg.no. IlcO 

10- Sizing Tool - l-Req Dwg Mo. H20 

11- Rough Facing Too! - l-Req. 5/d. 

12 - Holder- 2-Req. Sid. for 2-A - H/.&. S. T. L 

13- Fixture for Drilling - l-Req. Dwg No 8 Si 

14- Drill - l-Req. ?O m /mDia 

15- Jig for Centering - /• Req. Dwg. No. 834 

16- Centering Drill - l-Req Std 


y 



- 




\ 1 


..-.I' ) 



Fourth Operation 
Drill - F 




Sixth Operation 
Center -L 


BLANK 

MOTOR COMPANY 

TOOL LAYOUT FOR PISTON 

I st To 6™ OPERATIONS 

Date 8-24-17 

Drawn By HD 

166-1-6 

Scale 5"-* 1-0” 

QK.i VJSowtL 

L- 79 


FIG. 136. TOOL LAYOUT SHEET FOR PISTON—OPERATIONS 1 TO 6 











































































































































































PLANNING AND LAYING OUT WORK 


329 




Seventh OpeRatioh 
Reap Cross Slide Setting 
Finish Turn A 
Rough Grooves - 6 
Finish Radius-C 













^~F 


-n 


Eighth Operation 
Rough Bore - F 
Finish Bore -F 
Ream ■ F 


■Emery Wheel 




Seventh Operation 
Front Cross Slide Setting 
Finish Grooves-B 
Chamfer - G 
Rough Form-H 
Rough - / 


2 /-. 


Ninth Operation 
Drill • J 




Tenth Operation 
Grind - A 


Eleventh Operation 

/- Rough CrossShde Block- l-Req Dwa No ISIS *aho Ream - F 

2- Rough Grooving Tool - 3 Reg. Dwg. No 1379 

3- Finish Turning Tool - l-Req. Stdi 

4 - Finish Ra oius Tool - l-Req Dwg No. 1379 

5- Overhead Turret Attoch.-Std For *4 Umv. WAS. 

6- Turning Stem - TReq. Std. for *4 Univ. WAS. 

7- Center - l-Req Derg No 1378 

S- DraeBack Chuck- l-Req. Dwg No ISIS 
$-Finish Grooving Tool - 3 Peq. Dwg. No. I37S 

10- Forming Tool - I Reg. Dwg No. I37S 

11- Chamfering Toot - l-Req. Dug NO 1375 
/?- Oil Grooving Tool - l-Req. Dwg No 1375 

13- Finish Crass Slide Block - l-Req Dwg. No. 1375 
M- Center Bushing - /• Req. Dwg No 1375 

15- Jig for Bonny • t-Req. Dvrq.No. 836 

16- Rough Bonny Bar-l-Req. VwgNo 924 

17- Finish Bonny Bar -1-Req Dwg. No 924 

18- Reamer - t-Req. Dwg No 924 

19- Jig for Drilling - /-Req Dwg. No 835 

20- Drill - l-Req. 6 Dia 

21- Jig for Drilling - l-Req. Dwg No. 1462 

22- Drill- l-Req. I.S m /m Dia. 

23- Arbor Plug - l-Req. Dwg. No 978 

24 ■ Hand Reamer - T Req Dwg. No. 1292 


tiiNTM Operation 
Drill Hole !2'K 


BLANK MOTOR COMPANY 

TOOL LAYOUT FOR PISTON :7™ 

To 12™ OPERATIONS 

Date 8-27-17 Drawing By HD 

lbb-7-12 

Scale J*l : 0" OK. OloSiwd. 

L- 80 


FIG. 137 . TOOL LAYOUT SHEET FOR PISTON—OPERATIONS 7 TO 12 































































































330 


TOOLS AND PATTERNS 


same time, however, he takes up points in connec¬ 
tion with the manufacture, and makes sketches to 
give the tool designer his ideas concerning the fix¬ 
tures which must he made. These points are men¬ 
tioned in connection with the sixth point, follow¬ 
ing, but really the sketches are made directly in con¬ 
nection with the laying out of the operation sheet. 

6: Free-Hand Sketches.—The matter of making a 
sketch, preliminary to the designing of a tool or fix¬ 
ture, is of considerable importance, and the progres¬ 
sive tool engineer is systematic in this as in other 
respects. Therefore, when he makes a sketch for a 
piece of work, he does one of two things: he either 
makes the sketch on a loose-leaf pad and binds the 
sketch in a book kept for that purpose, in numerical 
order according to the piece number assigned 
to the work; or he attaches a sheet of sketches 
to the operation sheet. This latter method is not 
good, for the reason that these sheets can be easily 
lost, and may never be found. In which event, 
the tool engineer’s ideas may, or may not, be fol¬ 
lowed—there is no proof, in either case. It is a very 
simple matter to have a number of books, or even 
a note-book of plain paper, in which sketches can be 
kept The loose-leaf system, however, is much to be 
preferred, since, when that is used, the arrangement 
of the pieces in numerical order can be more easily 
kept. 

7: Making Layout Sheets.—The making of the lay¬ 
out sheets may be considered by the executive as a 
costly and unnecessary proposition, yet it will be 
found that in the long run the preparation of these 


PLANNING AND LAYING OUT WORK 


331 


sheets will save much time and expense. A lay¬ 
out sheet like that shown in Figures 136 and 137 is a 
picture of the various methods used in handling the 
work. The tools which are to be used in the work are 
indicated and are given a number, and anything of a 
special nature in the line of equipment is shown in 
sufficient detail to make the method used perfectly 
clear. These tool-layout sheets either may be made 
in connection with the tools, jigs, and fixtures which 
are being drawn up, or they may be made in ad¬ 
vance. If made in advance of the actual designing 
of the tools, it is necessary that the work should be 
done by a man of wide experience—one who pos¬ 
sesses the knack of sketching out an idea rapidly. 
Layout sheets of this kind are usually made one- 
quarter size, and the sheets may be so proportioned 
that they can be reproduced by a photostatic process 
and kept as a record with the operation sheets; or 
they may be bound in a separate book and kept for 
record. It will be noted, with respect to the sheets 
shown in Figures 136 and 137, that a complete rec¬ 
ord of tools used in the various operations is given 
at the bottom of each sheet, and that the drawing 
numbers used on each jig, fixture, or tool are specified 
in connection with this work. 

It is unnecessary, in making a layout sheet, to go 
into the smallest detail in regard to the design, but 
an effort should be made to represent a fixture which 
can be readily understood, and which will contain 
sufficient detail to show the methods used. One of 
the greatest advantages in a tool-layout sheet is in 
connection with turret-lathe operations. In the set- 


332 


TOOLS AND PATTERNS 


ting up of a turret lathe there are cases when an 
interference appears, and, unless a layout of some 
kind is made, this interference may not he noticed 
until the work is set up in the factory and the 
operator is ready to begin the work. When an inter¬ 
ference is not discovered until as late as this, it may 
cause a delay of several days in the production, 
and this delay may be a costly one to the manu¬ 
facturer. Looking at the matter from all stand¬ 
points, I believe that for work requiring a number of 
different operations, and for pieces of unusual char¬ 
acter, the use of a layout sheet is of great value. 
For small work which does not require anything 
elaborate in the line of special tooling, it may not 
be necessary to make such a layout, but even in 
cases of this kind the amount of labor involved is 
offset by the advantages gained. 

8: Time-Study Sheets.—There are two ways to 
make a time-study. One of these is to estimate the 
amount of time necessary to produce the work at 
certain speeds and feeds; the other is to take the 
actual time of the work in the factory. In the first 
instance, the man who makes the time-study must 
be a man of broad experience who is familiar with 
all kinds of machine tools, and one who has access 
to the tables giving the the speeds and feeds of 
which various machines in the shop are capable. In 
the second case, it is unnecessary to have a man of 
very wide experience, because he simply watches 
the work of the man in the factory and notes the 
amount of time taken for doing a certain piece of 
work. 


PLANNING AND LAYING OUT WORK 333 


TIME STUDY SHEET piece no.-"?".- 

BLANK MOTOR CAR CO. NAME Prston - 

DETROIT, MICHIGAN. MAT ILL - 


OPN 

NO. 

DESCRIPTION 

OF 

OPERATION 

TYPE c 

OF 

MACHINE F 

UTTING 

SPEED 

T. PER MIN 

DIAM. 1 

OF 

WORK 

.ENGTH 

OF 

WORK 

WIDTH 

OF 

>1) PEACE 

R.P. M. F 

OR 

STROKES S 

EED PER 

REV. 

OR 

TROKES 

.UTTING 

TIME 1 
MIN. 

ILOWANCC 

MIN. 

TOTAL 

2 

Rough Turn A 

2PP&J 

SO 

os% 

no 

- 

48 

0.040 

2 z 

2 k 



Rough Radius C 

«* 

•9 

t 

4 

y* 

99 






Allow for set up ondremoving 

vork 






h 

H 













3 

R.BcF. Bore ( D> 

*2A W&S 

so 

% m /m 

15 7m 

- 

48 

1.040 

% 

h 



Size <D> 



90 

S 

- 

48 

a 040 


>4 



Face (EKC.SI 

/■ 



t 

+ 

t 

t 

+ 




Allow for set up and remo/mg work, indexu 

ng etc. 




% 

/4 













4 

Dr/JI Hole F 

20“ DP 

SO 

20% 

587m 

- 

2 SO 

0.005 

JL- 

2 



Allow for set up and removing work, c/eaning 

j'9 e 

tc. 


/ 

3 













6 

Center End (Cl 

Sens Dr. 

60 

IO m /m 

!2 7m 

- 

S00 

Hand 

i 

4 

2 



and countersink 












Allow for set up and remov/ng work, c/eaning jig e 

•tc. 

















7 

Finish Turn (A) 

*■4 HAS. 

SO 

105 % 

HO 7m 

- 

48 

0.040 


A 



Rough Grooved (B) 

00 

40 

99 

67m 

- 

38 

0.006 

i 

A 



Finish - (B) 

$9 

30 

99 

67m 

- 

28 

0.006 

12 

A 



Form Rad. ( C) 

•9 

30 

9f 

2 % 

- 

28 

Hand 

/ 

2 

% 



Allow for setting and remov/ng, indexing and gaging 




2 

8* 













8 

Rough Bore < f> 

Co/burn 

SO 

227m 

58% 

- 

250 

0.0/0 

/ 

A 



Finish Bore (F> 

99 

SO 

•9 

99 


99 

09 

/ 

A 



Ream (F) 

99 

30 

•9 

99 

- 

150 

Hand 

1 

4 

A 

2 



Allow for re me 

wing and inserting tools an 

/ work 




2 

S 













e 

Drill <J> 

Sens Dr 

50 

67* 

67m 

- 

800 

Hand 

-A 

1 

2 



Allow for removing an 

q! inserting y 

■York 





% 

I4 













9 A 

Dri/t !2 Holes < K> 

Sens Dr 

60 

I.s7m 

6x!2 

- 

4000 

Hand 

14 

>2 


• 

A How for indexing, setting and ren 

loving 





t-2 

1 3 













10 

Grind O.D. (A) 

Norton 

4000 

Wheel 

!8- 

130 

- 

900 

00005 

0.000/ 

5 

54 



Allow for sett in 

q and removing work, gaging etc. 




% 

6 













II 

Hand Ream (F) 

Bench 

- 

- 

- 


- 

Hand 

- 

- 

Iz 














FIG. 138 . TIME-STUDY SHEET ON A CAST-IRON PISTON 








































































































































































334 


TOOLS AND PATTERNS 


It is entirely possible for an experienced man to 
determine very closely the amount of time which 
will be required for the performance of a given 
operation on any piece of work. His experience will 
tell him approximately what feed and speed can be 
safely used on the work, and as he can easily ascer¬ 
tain the length of the surface which he is about to 
cut, the time can be quickly estimated. A very good 
illustration of a time-study sheet is shown in Figure 
138; it will be noted that various columns are pro¬ 
vided for the different data used in connection with 
the estimates. The time-study sheet itself is self- 
explanatory. 

Now let us take up the method of figuring—or per¬ 
haps we should say estimating—the amount of time 
for a given piece of work, as indicated by the layout 
sheet. If the tool engineer is about to figure the 
time necessary on the work, his first step is to deter¬ 
mine the rate and settle the matter of cost of the 
tool. The best method of holding the work must al¬ 
ways be determined, and also the points from which 
the piece is to be located. Other matters in connec¬ 
tion with the design of tools and fixtures have been 
taken up in the previous chapters. 

9: Machine Tools Required.—After the time-study 
sheet, mentioned previously, has been made, the 
amount of time necessary with each machine can be 
easily determined, and in order to make sure that a 
sufficient number of machine tools are at hand to 
give the production necessary, and within the proper 
time, a record must be kept to show how many 
pieces are to be handled by any one type of machine, 


PLANNING AND LAYING OUT WORK 


335 


and how much of this machine time will he needed. 
The best way to determine whether the requisite 
number of machines is available, is to make a tabu¬ 
lated list of the various machines in the factory, 
and after the time-study sheet has been made, the 
amount of time which each piece consumes on a 
given type of machine can be tabulated in the list 
mentioned. In this way, as the work of the tool 
engineer progresses, it is very easy to see when 
any one machine or type of machine is overloaded. 
Then, when it is found that a certain type of ma¬ 
chine has more of a burden than it can reasonably 
be expected to sustain, some of the work which has 
been placed upon it can be transferred to some other 
type of machine adapted to the work. By using a 
process of this kind, and by carrying all these mat¬ 
ters along together, the matter of distribution of the 
work in the factory can be adjusted to the best ad¬ 
vantage. The last point can now be taken up by 
the tool engineer. 

10: Setting Piece-Work Prices.—The matter of set¬ 
ting piece-work prices does not strictly come under 
the head of the tool engineer’s work—the time-study 
sheet for the various operations on each piece of work 
is used by the cost department in obtaining a basis 
upon which to figure the cost of production. If the 
work 01 . the time-study sheet has been carefully 
done, the piece-work prices can be determined with 
great accuracy by the cost department, and the prices 
so set will be found to give excellent results. If, 
after a test has been made of the production time as 
indicated by the time-study sheet, there is found 


336 


TOOLS AND PATTERNS 


to foe a considerable difference in time, then the mat¬ 
ter should be immediately referred to the tool engi¬ 
neer for his attention. If it should be found that 
an error iias been made in his estimate of produc¬ 
tion, then the piece-work price may be changed to 
allow for the error On the other hand, if it is found 
that the workman is really consuming too much time 
in doing the work, the matter of speeds and feeds 
which he is using should be carefully looked into, 
in order that the source of the trouble may be deter¬ 
mined. 

Often I have found that the only reason why the 
production time did not check with the time-study, 
was that the operator was not using the speeds and 
feeds which would produce the best results. There 
are, of course, exceptional cases in which the work 
is of such a nature that the speeds and feeds which 
have been estimated upon cannot be used, but if this 
contingency occurs it is time for the factory super¬ 
intendent or the general foreman to step in and find 
out why the castings or forgings are not what they 
should be. 


CHAPTER XXII 


ESTIMATING COSTS 

Time Factor in Estimating Costs. —The problem of 
estimating costs of manufacturing work is one which 
is of interest to every manufacturer. In some cases 
a small factory is engaged in the building of jigs, 
fixtures, or other tools for outside concerns, and in 
many cases the firm which is doing the work is com¬ 
pelled to submit a bid in competition with other 
factories. It is therefore of the utmost importance 
to make sure that the bid which is submitted to the 
customer, is such that it stands a fair chance in the 
competition with the others. In order to make sure 
that the prices which are quoted to the customer 
are reasonable and proper, and at the same time that 
the estimate submitted is made with a wide enough 
margin to give a substantial profit to the manufac¬ 
turer, a careful estimate of the time necessary to 
produce these various pieces which are to be made, is 
a very important factor. 

Broad Experience Necessary.— This is one way in 
which the estimating of costs can be applied, but 
there are other applications which are fully as im¬ 
portant. Let it be supposed that a manufacturing 
concern is about to submit a bid for making up a 
large number of pieces which are components of a 
337 


338 


TOOLS AND PATTERNS 


military rifle; or that a great number of shrapnel 
shells are to be made, and that the bids which are 
to be submitted are in competition with those of 
numerous other manufacturers who are looking for 
the same work. It is very evident, then, both that 
the manufacturer who intends to do this class of 
work should be well prepared as regards his mechan¬ 
ical equipment of machine tools and shop tools, and 
also that his engineering force be well fitted to make 
estimates of production and of the costs of machin¬ 
ing. In the first place, either of the propositions 
mentioned requires the services of men who have had 
long experience in the shop, and also in the planning 
of operations for work which is to be done in quan¬ 
tity. 

Let us take the case of the factory which is pre¬ 
pared to build jigs and fixtures. It is much more 
difficult for a concern of this kind to make an esti¬ 
mate on the cost of a jig or fixture, than to estimate 
the production which can be obtained for certain 
pieces of work which are being put through the fac¬ 
tory in large quantities. In the case of the manu¬ 
facturing of jigs or fixtures, the work must be re-set 
a number of times during the process of manufacture, 
and every precaution must be taken to insure accu¬ 
racy. All these operations take a certain amount of 
time, the exact amount depending largely upon the 
skill of the tool-maker. It is therefore difficult to 
estimate this class of work as closely as the other 
kind mentioned. 

In the case of the manufacturing of a great many 
parts of the same kind, it is entirely possible for 


ESTIMATING COSTS 


339 


the manufacturer to provide means of holding and 
locating the work for the various operations which 
are to be done upon it in such a way that the parts 
will come to the desired size almost automatically. 
It is a matter of judgment. Unless the man who is 
selected for making estimates of this kind is one of 
broad experience, unless he has had a number of 
years of actual shop work, together with considerable 
experience in the actual engineering processes, and 
unless he has a logical mind, he is very likely to 
make a complete failure of estimating the cost of 
work which is to be done. 

Usual Causes of Failure. —If a jig or a fixture is 
to be made up, and there is a drawing from which 
the estimate can be made, the estimator can proceed 
to take up the various machining operations which 
are necessary to complete the piece of work, and can 
jot down the amount of time which he thinks it would 
be necessary to consume for the various operations, 
always remembering to make due allowance for the 
time lost by the tool-maker in looking up tools and 
in setting up the work preparatory to the machin¬ 
ing. Allowance must also be made for careful 
measuring, in order to insure proper accuracy in the 
finished product. It will be readily seen that in 
order to do this kind of work the estimator must be 
a man who has actually done the work in the factory, 
in order that he may know exactly how a man would 
be obliged to go to work to do the necessary ma¬ 
chining. The usual causes of failure in estimating 
a piece of work such as that mentioned, are that 
sufficient allowances are not made for the setting 


340 


TOOLS AND PATTERNS 


up and the getting ready to go to work, as well as 
for time which the man consumes in actually making 
the fixture. 

Secret of Estimating Costs. —Briefly stated, the 
entire secret of estimating costs of production lies 
in allowing a man sufficient time to do the work, 
remembering at the same time that there are little 
incidental things which tend to increase the time 
necessary, because of a failure to find a certain tool 
that is wanted, or owing to difficulties that arise when 
castings or forgings are not made in exactly the right 
way. All these points must be taken into consid¬ 
eration by the estimator, and the time allowance must 
be made on an hourly basis. The amount of profit 
which is to be made by the manufacturer is depend¬ 
ent, to a great extent, upon the overhead expense 
in the factory. There are many other items, also, 
which must be considered in making up an estimate 
of the cost of production. Among them are the 
matter of the cost of material. In some cases the 
jig or fixture is made of cast iron, and the pattern 
is to be made by the same person who is to build 
the fixtures. In a case of this kind, it is obvious 
that the pattern-maker’s time must also be charged 
against the account. Also, the amount of stock and 
the weight of the cast iron which goes to make up 
the jig, together with the cost of the iron in the 
jig, must be taken into consideration. 

Skilled and Unskilled Labor. —Due time must be 
allowed for the hardening of any parts of the jigs or 
fixtures which are to be hardened, and it must also be 
remembered that after a part is hardened, it is 


ESTIMATING COSTS 341 

usually necessary to grind it, in order that the dis¬ 
tortion caused by the hardening process may be re¬ 
moved and the piece may he properly fitted. Of 
course there are some parts which may be hardened 
without affecting the jig or fixture in its vital points 
in the process—for example, such things as the 
heads of screws or their points, a C-washer, a lever, 
or some other part of minor importance. No mat¬ 
ter how small the piece of work may be, however, 
it must be considered in the making of the jig or 
fixture, and if there are a number of pieces of the 
same kind (such as locating pins or something of 
similar character), several of these pieces can be 
made up at the same time by a boy or an apprentice, 
or by a comparatively inexperienced man. 

This being the case, the time for these various 
pieces need not be charged against the work at as 
high a rate as that charged for some of the actual 
tool-making. As a matter of fact, it is customary, 
in factories which do a considerable amount of this 
kind of work, to portion out such parts as can be 
made by an inexperienced man, and thus obtain the 
benefit derived from a cheaper rate of labor. In cases 
of this kind, the man who roughs out the part leaves 
a certain amount of work to be done or completed by 
the tool-maker, doing only the crudest part of the 
work himself. 

No Hard and Fast Rule.— There can be no definite 
rule which a man can follow in estimating costs for 
work of this character. As stated before, it is always 
necessary to make a generous allowance for the set¬ 
ting up time and incidental time needed by the work- 


342 


TOOLS AND PATTERNS 


men in obtaining tools from the tool room, and in 
making measurements, laying out the work, and so 
on. Let it be supposed that a number of jigs or 
fixtures of very similar character are to be made by 
a manufacturer for an outside concern. Then the esti¬ 
mator would consider that these various planing or 
shaping operations which are to be done on the work, 
can be carried along at the same time; if this plan 
be followed, a considerable saving in time will be 
effected. 

There are so many conditions which affect the 
building of tools of this type, that it is a very 
difficult matter to go into the details of the processes 
used in different factories. About all that can be 
said in this regard has already been mentioned. A 
specific example or two could be given, but they 
would not serve any valuable purpose, and might only 
confuse the reader. However, in the estimating of 
costs for work which is to be put through the factory 
in large quantities, other factors which are more nearly 
stable come into play. 

A Manufacturing Case. —Let us now consider the 
estimating of cost for a manufacturing proposition 
involving a number of pieces of a similar kind, 
which are to be made up entirely on an automatic 
screw machine. Under such circumstances it is a 
very simple matter to decide exactly which are the 
tools that must be used for the work, and since 
the material from which the work is to be made is 
of a certain character, and, furthermore, since the 
feeds and speeds of the machine can be easily de¬ 
termined, it is evident that a very close estimate of 


ESTIMATING COSTS 


343 


the actual time needed to produce the work can he 
obtained without great difficulty. Let us assume 
further that the job includes a number of pieces which 
must be machined on an automatic screw machine, that 
a series of holes must be drilled in each piece, and 
that a single milling operation is called for. It will 
be seen that although this piece of work is some¬ 
what more difficult to figure than the other one men¬ 
tioned, it is nevertheless, a simple manufacturing 
proposition. In this latter case, however, it is neces¬ 
sary to take into consideration the fact that certain 
tools and fixtures must be made, if the work is to be 
done properly and is to come within the required 
limit. A jig and a milling fixture will both be neces¬ 
sary. The cost of these fixtures must be estimated, 
and the price must be included in the cost which is 
submitted to the customer for whom the work is to 
be done. 

Overhead Expense. Hourly Basis.— The matter of 
overhead expense is so broad, and furthermore it is 
of such a variable character, that it is difficult to 
give anything more than a general idea of it in this 
chapter. Briefly, the overhead expense of a factory 
consists of a burden, or load, over and above the ap¬ 
parent cost of labor. That is to say, if a workman 
spends one hour in turning out a piece of work and 
if his rate is 30 cents an hour, this burden must be 
added to the workman’s actual cost of labor, in order 
that the cost of equipment, cost of power, and various 
other costs, may be taken care of properly. In addi¬ 
tion to these matters, the manufacturer’s profit, and 
the depreciation of his machinery and equipment 


344 


TOOLS AND PATTERNS 


must also be considered, together with the percen¬ 
tage on the investment, in order that when the work is 
completed there may be a large enough profit to 
prove to the manufacturer that his business is a 
profitable one.* 

It is evident that factories of different kinds and 
under different management would have a proportion 
of overhead expense that would differ according to 
the factory conditions and many other items pertain¬ 
ing to the management. In the past few years I 
have noted a wide difference between the bids sub¬ 
mitted by different manufacturers on the same jigs 
and fixtures. This difference in prices makes it clear 
that either there is a tremendous difference in the 
way in which different manufacturers estimate on the 
same piece of work, or else the equipment which these 
various manufacturers use for producing the work 
is in some cases better adapted than in others to the 
class of work on which these prices were submitted. 

Different Methods but One Principle. —One particu¬ 
lar instance is worthy of mention. A set of blue¬ 
prints of a group of three indicating gauges was sent 
to five different manufacturers, with a request for 
bids. The lowest bid received was $670, the highest 
bid was $1472. The work was given to the man 
whose bid was the lowest, and the work produced was 
of so high an order that it passed a most rigid inspec¬ 
tion. It is evident from this case that the manu¬ 
facturer whose bid was the highest would have been 


* A full discussion of the factors affecting the determination of 
burden or overhead will be found in Industrial Cost Finding, by N. T. 
Ficker, Vol. 10, Factory Management Course. 



ESTIMATING COSTS 


345 


able to make a very high profit on the work, had he 
succeeded in obtaining the contract, or that his 
operating methods were very inferior. As a matter of 
fact, I have found that many manufacturers who hid 
upon this class of work do not go to the trouble of 
figuring out all the details of manufacture carefully, 
hut merely look over the work and form a rough 
estimate from their previous knowledge of how long 
it takes to do the work. To be sure, a man of wide 
experience can, even by this method, obtain a close 
approximation of the time necessary to produce a 
given piece of work, always provided that this man 
has had experience with other work of a similar kind. 
On the other hand, a careful estimator who has had 
the necesary shop experience and many years of 
actual shop training, can obtain a much closer ap¬ 
proximation of the cost of production by figuring out 
the actual amount of work which must be done to 
complete the piece. 

Evidently, then, different processes of estimating 
cost are used by different manufacturers. It is hard 
to say just what method is best suited to a particu¬ 
lar class of work, since so many factors enter into 
the matter. It is always safe, however, to act upon 
the principle that the careful estimator who figures 
the work on the hourly basis will obtain, in the long 
run, a much more uniform and satisfactory estimate 
of cost than the man who depends upon snap judg¬ 
ment. Each manufacturer must be a law unto him¬ 
self in this regard, but the careful man, who adopts 
the principle of “safety first,” will find himself better 
off than the one who uses the “hit or miss” method. 


CHAPTER XXIII 


INTERNAL, EXTERNAL AND THREAD GAUGES 

Accuracy Required in Interchangeable Manufac¬ 
ture. —When a number of parts are to be made that 
will be interchangeable one with another, it is neces¬ 
sary to make the parts within definite limits of accu¬ 
racy. Before going into this subject let us first under¬ 
stand the different terms which apply to gauging and 
gauging systems. Let us also determine the use of a 
gauge and its applications to the work. 

In the first place in assuming that a number of pieces 
of the same size are to be made, it will be necessary 
for the workman to measure each piece as he is pro¬ 
ducing it in order to be sure that the sizes are kept 
to the dimensions, unless a system of gauges is 
made for the work. He would use for this pur¬ 
pose a set of micrometer calipers and other measuring 
instruments of precision depending upon the class of 
work on which he was engaged. But as these instru¬ 
ments are all capable of being set to certain sizes, and 
are, therefore, flexible, it is obvious that in using these 
tools he must be able to discriminate in their applica¬ 
tion. He must guard against error in reading the 
micrometer, or other instruments. And, again, the 
continual use of such delicate instruments in manu¬ 
facturing is not to be commended on account of the 
346 


INTERNAL, EXTERNAL AND THREAD GAUGES 347 


wear involved. In order, then, to take the place of 
these delicate instruments, especial gauges can be 
made to give fixed readings; also in order to provide 
for slight variations in the work, “limit” gauges can 
be used. 

Let it be supposed that automobiles are to be made 
up in large quantities complete in every part and on 
an interchangeable basis, such that one part if injured 
or worn out can be replaced by another which will be 
the counterpart of the previously used portion. 
Assuming that a condition of this kind is found, the 
first step in the gauging system must be a determina¬ 
tion of the different kinds of fits which will be used in 
the different parts of the automobile. In this connec¬ 
tion the quality of the product must be taken into con¬ 
sideration. That is to say, if an excellent machine is 
to be manufactured, the workmanship will be natu¬ 
rally of a high grade and, therefore, the allowances for 
the various fits must be consistent with the quality of 
the machine to be manufactured. Let us consider this 
matter in detail under the various headings given here¬ 
with. 

Terminology. —When two parts are to be fitted to¬ 
gether the relation of these parts to each other is in 
the nature of a fit of some kind. For example when a 
shaft is to be fitted to a bearing in such a way that it 
will revolve freely in the bearing, the fit will be called 
a “running fit”. A “push fit” is somewhat closer than 
a running fit; the parts are not free to revolve, but can 
be assembled by hand without using much pressure. A 
“drive fit” is such that the parts can be assembled only 
by means of pressure under an arbor press or by driv. 


348 


TOOLS AND PATTERNS 


ing with a hammer. A “force fit” is such that the 
parts must be assembled by means of heat and hydrau¬ 
lic pressure. 

It is evident that there may be several kinds of run¬ 
ning fits; that is, there may be several grades of these 
fits. If we should assume that a farm machine, such as 
a harvester or mowing machine, was to be made, it 
would be apparent that such a machine subjected as it 
is to heavy usage and in the hands of men who are not 
mechanical, would need to be rather freely put together. 
This class of fit would obviously be less accurate than 
if the machine in question were to be an automobile or 
a sewing machine or some other type of mechanism 
requiring careful workmanship. Therefore it is plain 
that several grades of running fits must be made to suit 
different kinds of work. These matters are entirely 
dependent upon manufacturing conditions and also the 
requirements of the mechanism after it is completed. 

Manufacturing conditions are such that it is easier 
to make shafts or studs to a size a little under or a lit¬ 
tle over a specified dimension than it is to make a hole 
over or under a given size. This is due to the fact that 
a hole is usually drilled, bored, reamed, or ground. It 
is not a very easy matter to make a reamer so that it 
will cut a hole much different from the standard size 
(although a new reamer is inclined to cut a trifle over¬ 
size, and after it is worn a little it may cut a little 
under-size). Therefore the size of the holes are usually 
kept as nearly to a standard as the uses of tools will 
permit. As a general thing it is not customary to put 
any kind of a limit on a hole which is to be drilled, but 
holes which are to be reamed or ground can be 


INTERNAL, EXTERNAL AND THREAD GAUGES 349 

machined within close limits of accuracy. It is well to 
state parenthetically at this point that as the hole is 
usually made as nearly standard as possible the limits 
of accuracy within which it must be machined are de¬ 
termined by conditions. The shafts or studs, however, 
which fit the holes are made within limits determined 
by the class of fit for which they are intended. 

Terms Used in Gauging.— In mentioning the terms 
used to describe various points in connection with 
gauging, there are three words the meaning of which 
are not always clear to the average man. These terms 
are ‘ ‘ allowance, ” “ tolerance, ” and “ limit. ’ ’ 

The term allowance is used to describe the relation 
that one piece bears to another when the two parts are 
assembled. For example, if a shaft were to be fitted 
into a hole so as to revolve freely, it would be neces¬ 
sary to make an allowance between the size of the hole 
and the size of the shaft so that the right relation will 
be maintained between the two surfaces and permit the 
shaft to revolve with the proper amount of clearance 
and sufficient freedom in the hole. If a hole were to 
be reamed to 1 inch in diameter and a shaft were to be 
revolved in this hole, we can assume that an allowance 
of 0.001 inch must be made on the shaft under the size 
of the hole so as to permit free turning. It will be 
cipally to the kind of fit which must be obtained be¬ 
tween two pieces of work. Allowance is determined by 
the kind of fit which is to be made. 

The term tolerance applies to the total amount of 
variation permissible in manufacturing any given piece 
of work. As an example, let us take a shaft 1 inch 
in diameter which must be machined to a given size. 


350 


TOOLS AND PATTERNS 


Tolerance is determined by the machining possibilities 
and the quality of fit which is to be made. If it is sup¬ 
posed that the shaft is to be machined within a toler¬ 
ance of 0.0005 inch, then the maximum and minimum 
variations must not differ by more than the amount 
mentioned. 

The term limit is applied to the maximum and mini¬ 
mum size of work to be produced as determined by the 
tolerance. For example, if the work is to be made 



FIG. 139. DIAGRAM SHOWING APPLICATION OF LIMITS TO A 
SHAFT AND HOLE 


within a tolerance of 0.0005, then the limits within 
which the piece may be permitted to vary must be such 
that their total amount will not exceed the prescribed 
tolerance. 

Let us take a concrete example of the shaft and hole 
diagramatically shown in Figure 139. This illustra¬ 
tion shows that the limits as set for the dimension of 
the hole are given in terms of plus (+) and minus (—). 
It will be seen that the shaft sizes are also given in 
limits but that the limits are both minus dimensions. 













INTERNAL, EXTERNAL AND THREAD GAUGES 351 

From the figures given on the diagram, the greatest 
amount of variation possible is as follows: 

Maximum hole = 1.00025 

Minimum shaft — 0.098 

Clearance = 0.00225 

Minimum hole = 0.99975 

Maximum shaft = 0.999 

Clearance = 0.00075 

From the diagram and the foregoing figures it will 
be seen that in such extreme cases the allowance or 
clearance will be sufficient to obtain a running fit for 
the shaft in the hole. It is true that in the greater 
extreme the clearance is a little more than it should be, 
while in the smaller allowance the fit is a little closer 
than it should be; but if the gauges which are used for 
the work are properly used, there will be no doubt that 
the fits obtained are commercially good. 

The principles shown in this diagram can be applied 
to other kinds of gauging, and it is an easy matter to 
determine whether the proper allowance, tolerance, and 
limit have been set for any given piece of work by 
means of a careful inspection of the results in maxi¬ 
mum and minimum sizes obtained by following the 
limit given. 

Setting Limits for Interchangeable Work. —Gauging 
work in order to produce interchangeable parts is de¬ 
pendent upon so many factors that it is out of the 
question to give hard and fast rules here that will be 
applicable to all conditions. Manufacturers have 
established no system of limits which fit every con- 




TOLERANCES FOR STANDARD HOLES 





5 

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ooo 

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Nominal Diame¬ 
ters, Inches.. 


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adl 



352 


Max. Limit .+0.00050 +0.00075 +0.00100 +0.00125 +0.00150 +0.00175 +0.00200 +0.00225 +0.00225 +0.00250 +0.00250 +0.00275 +0.00275 

Min. Limit .—0.00050 —0.00050 —0.00050 —0.00075 —0.00075 —0.00075 —0.00100 —0.00100 —0.00125 —0.00125 —0.00125 -0.00125 —0.00150 

Toleranee . 0.00100 0.00125 0.00150 0.00200 0.00225 0.00250 0.00300 0.00325 0.00350 0.00375 0.00375 0.00400 0.00425 






















































TOLERANCES FOR RUNNING FITS 
(NEWALL ENGINEERING CO.) 


















































































TOLERANCES FOR PUSH, DRIVING AND FORCE FITS 


• 

o 

o 

o 

2 

KH 

K 

W 

w 

2 

O 

z 

w 

£ 

w 

z 


CM 

rH 

1 

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- 0 . 002 C 0 

— 0.00075 

0.00125 


+ 0.00700 

+ 0.00500 

0.00200 


+ 0.02400 

+ 0.02200 

0.00200 

1 

* 


oo»o 

OMM 

(MOr- 

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* 0*0 0 

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—0.00200 

— 0.00075 

0.00125 


+ 0.00600 

+ 0.00450 

0.00150 


+ 0.02000 

+ 0.01800 

0.00200 

© 

1 


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*0 »o o 

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»o o »o 

CQ»ON 

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o o o 
o o o 


ooo 
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Tt* CO *-H 

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CM CM 

T-H V—H f— 

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TT° 


ooo 
+ + 


ooo 

++ 

CO 

1 

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*0 

p* 

CO 

CO 

P 

— 0.0010 
— 0.0005 

0.0005 

Q 

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9 

+ 0.00400 

+ 0.00300 

0.00100 

.u 

m 

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p 

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CM O CM 

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++ 

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r 

CO 

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co 

— 0.0010 
— 0.0005 

0.0005 

T 

CO 

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+ 0.00350 

+ 0.00250 

0.00100 

T 

00 

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+ 0.01000 

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0.00200 

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cm 


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— 0.00075 
— 0.00025 
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+ 0.00150 
0.00050 

X 

ei, 


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ooo 

++ 


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++ 

Nominal Diame¬ 
ters, Inches... 


Max. Limit_ 

Min. Limit. 

Tolerance. 


Max. Limit. 

Min. Limit. 

Tolerance. 


Max. Limit. 

Min. Limit. 

Tolerance. 


354 













































































INTERNAL, EXTERNAL AND THREAD GAUGES 355 

dition, and there is more or less diversity of opinion. 
Tables used by the Newall Engineering Co. are given 
on the preceding pages which may be helpful to a 
manufacturer in establishing a system of limits for his 
own factory. As previously stated, the class of work to 
be done has a great effect on the setting of limits for 
interchangeable manufacture, but a basis from which 
to work can readily be established and suitable changes 
made to suit requirements which later may be found 
necessary. 

The man who establishes a system of manufacturing 
limits for interchangeable manufacture must always 
understand the requirements of the work to be done and 
its nature. He must know just where the finest work¬ 
ing parts of the mechanism are situated and how 
closely these parts must be fitted in order to give the 
results required. The conditions of manufacture must 
always be considered, and the vital parts of the 
mechanism must have special attention. As pre¬ 
viously mentioned, tolerances for all work should be as 
great as possible consistent with the quality of the 
work to be produced. 

In this connection it is well to mention the unfor¬ 
tunate practice of the majority of manufacturers in 
regard to shaft lengths. It is seldom that they pre¬ 
scribe limits on this class of work, and therefore the 
workman in making a shaft is unable to determine 
how closely the shoulders must be made to the given 
sizes on the drawing. In order to obviate any trouble 
in this regard it is good practice to establish a system 
of some sort to govern such work. It must always be 
remembered that small tolerances mean careful work 




356 


TOOLS AND PATTERNS 


and that careful work is always expensive. Therefore 
it is highly advisable to specify the limits on shafts 
and shoulders in order to obviate difficulties in machin¬ 
ing. It is frequently possible to give shoulder toler¬ 
ances on shafts of 1/64 or 1/32 of an inch, and when 
it is possible to give such tolerances the cost of 
machining will be much more reasonable. 

Many manufacturers set tolerances entirely too 
close in the effort to obtain a fine product. Some 
even go to the expense of finishing parts which do not 
fit others in order to improve the appearance of the 
finished product. Such practice as this is expensive 
and unnecessary, except in cases where parts must be 
balanced on account of the high rate of speed at 
which they are to run or else to prevent vibration 
due to excessive speed and lack of perfect balance. 
All these points must be considered in the setting 
of limits, and therefore it is very obvious that the 
engineer who does this work must be perfectly fa¬ 
miliar with the product in its actual working points. 

Marking Limits on Drawings.—The marking of 
drawings with limits is commendable, and much con¬ 
fusion can be avoided by using fractional dimensions 
for all unimportant sizes. A notation can be made 
on the drawing to the effect that an error of 1/64 + 
or — is permitted on fractional dimensions given on 
the drawing. Decimal dimensions can also be used 
to indicate tolerances to a certain degree, although 
this practice in general is not recommended. There 
may be a notation or an understanding in regard to 
the matter, however, such that if decimal dimensions 
are given to four places of decimals, the work must 


INTERNAL, EXTERNAL AND THREAD GAUGES 357 

be kept within a limit of plus or minus 0.0005; if 
three places of decimals are given on a drawing then 
the limit is to be kept within 0.001 plus or minus; 
if two places of decimals are given on the drawing 
then it may be understood that a limit of 0.005 plus 
or minus is permissible. The better way, however, is 
to mark the drawings positively with the limit when¬ 
ever possible, so that there is no chance for errors on 
the part of the workman. 

Internal Limit Gauges,—If it is necessary to ma¬ 
chine a hole within certain limits of accuracy, a 
gauge should be provided which is so constructed as 
to permit the workman to use it in determining 
whether he has produced the work within the. re¬ 
quired size or not. If the hole to be measured is a 
cylindrical one of small size, say 2 or 2% inches, then 
the type of gauge which is used is termed a plug 
gauge. And if the hole to be gauged is tapered, the 
type of gauge used is termed a taper plug gauge. If 
the hole is threaded, the gauge used is called a male 
thread gauge. These three gauges are of different 
types and are made differently to suit the various 
kinds of work for which they are to be used. 

A limit gauge is a gauge so constructed as to de¬ 
termine more or less automatically whether work has 
been made within the specified limits or not. There 
are several types of gauges for this purpose, which 
differ from each other only in certain details ot con¬ 
struction; the principles on which they are based are 
the same. The type used for gauging a cylindrical 
hole has one end made of such size that it will just 
enter the hole providing the hole has been made large 


358 


TOOLS AND PATTERNS 



FIG. 140. SEVERAL VARIETIES OF PLUG GAUGES 


enough; the other end is very slightly larger than the 
hole should be, the difference in size being the ex¬ 
treme limits or tolerance permitted in the work. 
Therefore a gauge of this kind is frequently spoken 
of as a “go and not go” gauge, meaning that one 
end should go into the work and the other end should 
not go. Sometimes the go and not go portions are 
on the same end of the gauge. 

Referring to Figure 140, the two types of gauges 
commonly used will be noted at A and B. The 
upper figure, A, shows the double-end plug gauge, 
and the lower figure, B, has both of the limiting 
portions on one end. The lower type, B, is to be pre¬ 
ferred for work in which the hole extends com¬ 
pletely through the piece, as the workman in this 



























































INTERNAL, EXTERNAL AND THREAD GAUGES 359 

case is not obliged to turn the gauge end for end in 
using it. These gauges are often made with a slight 
taper on the end, in order to facilitate their use. 

Another type of plug gauge for cylindrical work is 
shown at C in the same figure. This gauge does not 
differ from the one indicated at A in any respect ex¬ 
cept that the go and not go portions are made in the 
form of bushings which can be removed and replaced 
with others in the event of their becoming worn. 
Although gauges of this kind cost a little more to 
produce, they have many advantages, which are 
plainly apparent, in the line of upkeep. 

Internal Taper Gauges.—The gauging of a tapered 
hole is an entirely different proposition from the 
gauging of a cylindrical one, for two gaugings are re¬ 
quired, namely, the taper itself and the diameter at 
the large end of the hole. It is obvious that a 
tapered hole is made to fit a tapered shaft or some¬ 
thing of similar nature. In a gear which is made 
with a taper hole, for instance, the gear must be 
made to mesh correctly with its mate, and therefore 
its longitudinal position on the tapered shaft is im¬ 
portant. This means that the tapered portion must 
be of such a diameter at the large end that it will 
slip upon the tapered shaft to a definite distance 
and fit snugly on the shaft at the same time that it 
attains its correct position longitudinally. It is plain, 
then, that a gauge for such a piece of tapered work 
must be so made that it will determine the taper as 
well as the distance that the actual fit will take 
place on the shaft. 

As it is rather difficult to measure a tapered hole 


360 


TOOLS AND PATTERNS 


at the large end, or in fact in any other portion of 
the hole, without special instruments. The method 
used in gauging the diameter is by the distance that 
a marked section of the gauge enters the large end 
of the work. By reference to Figure 141, the type 
of gauge used for a tapered hole will be clearly 
noted. This gauge is a limit taper gauge, and the 



FIG. 141. TAPER LIMIT GAUGE FOR INTERNAL TAPERED HOLE 


limiting portions are determined by the flatted part, 
B, on one side of the gauge and the cylindrical por¬ 
tion, C, which extends beyond it. Now when this 
gauge is used in a tapered hole, the operator places 
it in position and notes whether the flatted portion is 
below the surface of the hole or not. If he finds 
that it is below the surface and that the opposite 
side of the gauge, C, remains slightly outside of the 
work, then he is certain that the work has been made 
within the required limit longitudinally. 

In addition to the longitudinal dimension, how¬ 
ever, it is necessary to determine whether the taper 










INTERNAL, EXTERNAL AND THREAD GAUGES 361 



FIG. 142. FEMALE MASTER GAUGE FOR TESTING MALE 
TAPER GAUGES 


is correct or not. As a general thing the taper in a 
hole is determined by means of a special tapered 
reamer and, therefore, there is little chance for varia¬ 
tion at this point. However, in order to determine 
the taper with certainty, the inspector may use a 
little Prussian blue on the gauge and by revolving 
it slightly in the hole, he may see whether it is in 
contact along its entire length or not. 

In connection with the use of taper gauges and, in 
fact, other types of gauges, mention should be made 
of the necessity for reference gauges. Gauges of 
this kind are made with great care and should, be 
kept in a safe place so that they will not be subject 
to injury or marked variations in temperature. It 
is apparent that a reference gauge for a male taper 
gauge, such as that just described, would be such 
that when placed in conjunction with the reference 
gauge any variation might be readily detected. A 





































362 


TOOLS AND PATTERNS 


male gauge is usually tested by placing it in a 
female gauge, and conversely a female gauge is 
tested on a male gauge. 

When a number of tapers of different diameters 
but of the same angle are to be tested, a reference 
gauge like that shown in Figure 142 can be readily 
made. This gauge is marked with the piece numbers 
and the limits in such such a way that the accuracy 
of the gauge to be tested can be quickly determined. 
This gauge is made with three adjustable blades of 
steel to facilitate manufacture. After the gauge has 
been set properly by means of suitable measuring in¬ 
struments, the screw holes can be filled with wax or 
composition so that they cannot be tampered with. 

Male Thread Gauges,—When an internal thread is 
to be gauged the type of gauge used is generally 
called a male thread gauge. The gauging of a thread 
requires special precautions as there are so many 
points to be determined: First, there is the diameter 
of the thread at the pitch line; second, the angle of 
the thread; third, the diameter of the hole at the 
bottom of the thread; fourth, the lead of the thread.* 
The ordinary commercial gauge only gives an ap¬ 
proximation of these four points, otherwise several 
gauges would be needed to determine whether a 
thread was correctly made or not. 

The simplest form of thread gauge is a piece of 

* The lead of a thread is the distance from the center of one 
thread to the center of the next, measured longitudinally. That is, 
in a 16 pitch thread, the lead is inch, because there are 16 threads 
to the inch. On multiple threads, i. e., double or quadruple threads, 
lead denotes the longitudinal distance from one thread to the same 
thread after it has passed once around the piece. Thus the lead of a 
16 pitch thread quadruple, would be 4x^ = y 4 inch. 



INTERNAL, EXTERNAL AND THREAD GAUGES 363 

steel threaded on both ends, one end of which is 
made so as to enter the threaded hole and the other 
end slightly larger so that it will not enter the 
threaded hole. This type of gauge is clearly shown 
in Figure 143. Commercially, a gauge of this type 
gives results sufficiently close to the limit. 

The majority of threaded holes are made by taps, 
and if the thread gauge does not enter the work 
freely, it is generally found that something is the 



FIG. 143. STANDARD TYPE OF MALE THREAD GAUGE 


matter with the tap that has been used. The taps 
should then be examined to find where the error lies 
and be discarded if found faulty. In most cases it 
will be found that a variation in the lead is the cause 
of the trouble. The tap may have been made up 
properly and have changed considerably during the 
hardening process, so as to give a lead slightly dif¬ 
ferent from what it should be. It is an easy matter 
for a workman to tap a hole to the proper size, but 
if the lead of his tap is incorrect, great difficulty may 
be found in assembling the parts after they have 
been machined. A variation in the lead of the thread 











364 


TOOLS AND PATTERNS 


means that only a few threads will be doing all the 
work while the other ones are free. 

Several instruments are made for measuring the 
lead of a screw, based on the pitch line measure¬ 
ment. Usually these instruments are provided with 
ball points to reach down into the thread and 
measure directly on the pitch line. The type of 
thread gauge shown in the illustration is practically 
the only one which is commercially used today. The 
amount of tolerance permitted should never be more 
than 70 to 80 per cent of a full thread. 

Some gauges are made in such a way that a por¬ 
tion of the gauge will act as a plug to measure the 
root of the thread or, really, the diameter of the 
hole. In this case the thread itself is measured sepa¬ 
rately. The majority of commercial screws are made 
with two much clearance; this results in a loss of 
strength and is productive of considerable difficulty 
when used on machinery otherwise all right. The 
result of poor workmanship on threaded work is that 
the threads, not having a full bearing, strip easily 
and are generally useless. The limit on threaded 
work should be sufficient to avoid such conditions. 

External Gauges.—External gauges are made for 
cylindrical, taper, or threaded work. There are sev¬ 
eral kinds: snap gauges, ring gauges, receiver gauges, 
and female thread gauges. The snap gauge is the 
most common and is used for gauging cylindrical 
work. The ring gauge is generally used for reference, 
although occasionally it is used for actual gauging 
processes. Receiver gauges are made for determining 
several diameters at the same time and also for taper 


INTERNAL, EXTERNAL AND THREAD GAUGES 365 



FIG. 144. STANDARD TYPE OF SNAP GAUGE WITH 
ADJUSTABLE POINTS 


work. The female thread gauge is.used for gauging 
male threaded work, such as screws and the like. 

In gauging cylindrical work which is to he held 
within definite limits of accuracy, the snap gauge 
shown in Figure 144 is commonly used. This gauge 
is provided with surfaces or pins which limit the 
amount of variation, as shown at A and B in the 
illustration. The “go” portion of the gauge is rep¬ 
resented at A; the “not go” at B. This gauge is 
used directly on the work and is extremely simple. 
As an example, let us suppose that a piece of cylin¬ 
drical work is to he held within the dimension 0.998 
and 0.996. Then A would he made 0.998 and B, 
0.996; hence if the work were to he made so that it 
will enter A and not go between the points B, it is 












366 


TOOLS AND PATTERNS 



FIG. 145. SNAP GAUGE FOR FIG. 146. TEMPLET GAUGE FOR A 
MORE THAN ONE DIMENSION SPECIAL STUD 


sure to be right. When this gauge becomes worn, 
the points A and B can be adjusted by size blocks or 
reground to size. In order to avoid either acci¬ 
dental or intentional changes, it is well to pour 
melted wax into the holes at the adjustable points, or 
else to put a drop or two of solder at these points so 
that no change can possibly be made without per¬ 
mission from the inspection department. 

Snap Gauges for Widths.—Gauges of the snap 
variety are also used for determining widths across 
lugs and between them, for shoulder distances on 
shafts, for distances between bearings, and for other 
work of like character. Sheet metal gauges are fre¬ 
quently made for this purpose, and several gauging 
points can be made on a single gauge. For example, 
having a casting, such as shown above in Figure 145 
in which the dimensions A and B are to be gauged, 
a snap gauge similar to that shown in the lower por- 
























INTERNAL, EXTERNAL AND THREAD GAUGES 367 

tion of the figure can be employed. This type of 
gauge is made up of sheet steel, usually % to 3/16 
inch in thickness, and hardened after it has been 
made very close to size. After the hardening, the 
gauging points or surfaces are carefully ground to 
correct dimensions. Gauges of this kind can be used 
in confined situations, and as they can be cheaply 
made their use is almost infinite. 

Templet Gauges. —Frequently it is necessary to 
determine the form of a piece of work after it has 
been machined, especially when the shape of the 
piece is more or less irregular. Take as an example 
the work shown in Figure 146, in which the general 
form and correct spacing of A, B, and C are essential. 
In a case of this kind a templet gauge, similar to 
that shown at D, can be made to the form desired 
and the workman can use it when making up the 
piece, applying it to the work from time to time to 
obtain correct spacing and form. 

The templet gauge as ordinarily used is not, how¬ 
ever, an accurate method of gauging for it does not 
“tell the story,” but only determines whether the 
shape of the work is correct or not. It does not show 
just where the points of inaccuracy are, but it does 
show that the piece is not correct if it does not fit 
the gauge. When it is necessary to gauge the con¬ 
tour of a piece of work within close limits of accu¬ 
racy, another type of measuring instrument, termed 
an indicating gauge, can be used. This type will be 
described in the next chapter. 

Perhaps one of the most useful applications of the 
templet gauge is in the manufacture of bolts, cap 


368 


TOOLS AND PATTERNS 



screws, studs, and the like, for determining the 
length of the work and the length of the thread. As 
an example, let us take the screw shown in Figure 
147 in which the length, A, is 3 inches and the length, 
B, of the thread, 2 inches. A gauge can be made for 
this work similar to that shown in the lower part of 
this illustration. Its application is obvious: both the 
length of the work and the thread can be noted in an 
instant when the gauge is applied. Jhere are many 
other uses to which the templet gauge can be 
adapted, and the forms used are naturally dependent 
upon the work to which they are to be applied. 

Ring Gauges for Cylindrical Work.—Ring gauges, 
such as that shown in Figure 148 at K, are used in 
a large degree for reference, but they are also occa¬ 
sionally called for in connection with manufacturing 



































































INTERNAL, EXTERNAL AND THREAD GAUGES 369 


on certain classes of work. The ordinary snap gauge 
as used on cylindrical work simply gives the diameter 
of the work at certain places where it is applied, but 
it does not show the variations along the shaft, nor 
does it determine whether the work is uniform in size 
at all points. 

Let us take the piece of work shown in Figure 148 
as an example: Here we see a shaft on which another 
member is to have a sliding fit from A to B. In 
gauging this shaft, the snap gauge would be used at 
two or three points, as at C, D, and E, and it will 
be assumed that the remainder of the shaft is correct, 
providing these points pass the inspection. By re¬ 
ferring to the exaggerated view, much enlarged, of 
the same shaft, it can be seen that if the work is 
found to be imperfect, as shown at F, G, and H, the 



FIG. 148. CYLINDRICAL RING GAUGE, SHOWING APPLICATION 
























370 


TOOLS AND PATTERNS 


snap gauge will not reveal the defect. But if the ring 
gauge, K, were to be passed over the work from A to B, 
the trouble would be located immediately. For work 
of this kind, therefore, the snap gauge can be used 
as a work gauge and the ring gauge for the final in¬ 
spection. The workman can then gauge the work for 
diameter, and the inspector’s test with the ring gauge 
will show any variations along the length. 

Receiver Gauges.— On certain classes of work, such 
as the components of rifles, sewing machines, type¬ 
writers, and adding machines, it may be found neces¬ 
sary to gauge every part of the piece as a final check 
against errors in machining. In this work a receiver 
gauge can be employed to advantage. This instrument 
is so made that the work can be placed in the gauge 
itself, and if /the piece of work has been correctly made 
within the required limits of accuracy, it will conform 

















INTERNAL, EXTERNAL AND THREAD GAUGES 371 

closely to the contour of the receiver. Gauges of this 
kind can be made as limit gauges if desired/ either by 
making them up with a series of sliding points to in¬ 
dicate the limits of variations permissible, or by 
making two gauges in one of which the work must 
go and in the other not go. Sometimes it is neces¬ 
sary to gauge a contour very carefully, and in cases 
of this kind an indicating gauge can be employed, as 
described in the next chapter. 



FIG. 150. RECEIVER GAUGE FOR A POPPET VALVE 


A common form of receiver gauge is that shown in 
Figure 149, which is made for taper pins. Reference 
to the illustration will show that it consists of a base 
plate and two blades, one of which may or may not be 
adjustable. In using this type of gauge the pin is 
simply laid between the two blades in order to note 
whether the taper corresponds to that of the gauge 
or not. An additional refinement can be incorporated 
in this gauge by placing a mark on one of the blades 
to gauge the diameter of the taper pin by determin- 
ing its length. 

















372 


TOOLS AND PATTERNS 


Another application of the receiver gange is shown 
in Figure 150. This gauge is made for a poppet 
valve, in order to test the concentricity of the stem, 
A, and the valve seat, B. In addition to these points 
the angle of the seat can also be gauged. It will be 
noted that a part of the collar, C, is cut away to 
permit inspection along the seat of the valve. Many 
applications of this type of gauge can be made when 
the nature of the work warrants it. 

Taper Ring Gauges. —In gauging a taper shaft or 
work of similar character several varieties of gauges 
may be used. These gauges are usually made from a 
cylindrical piece of steel having a tapered hole, such 
as that shown in Figure 151 at A. The limits are 
taken care of by cutting away half of the gauge at 
the large end, as noted at B. The correct size is de¬ 
termined by the junction of the tapered portion with 
the cylindrical part and the position of the gauge 


A 



FIG. 151. FEMALE TAPER LIMIT GAUGE 















INTERNAL, EXTERNAL AND THREAD GAUGES 373 


longitudinally on tlie work. The gauge should not 
push onto the work far enough so that the flat part 
comes beyond the junction of the tapered and the 
cylindrical part. The taper itself is found to be cor¬ 
rect or not by placing the gauge in position on the 
work which has been coated with a thin film of Prus¬ 
sian blue and giving it a slight turn to determine 
whether the taper is touching at all points. 



FIG. 152. MALE MASTER GAUGE FOR TESTING FEMALE 
TAPER GAUGES 


Master Taper Gauge for Female Gauges. —As a 

reference gauge to which a female gauge may be 
applied in order to determine whether it is correct or 
not, a form such as that shown in Figure 152 can be 
advantageously used when all of the tapers to be 
gauged have the same angle. This gauge was de¬ 
signed to go with the female gauge shown in Figure 
142. But in this case the gauge is intended for test¬ 
ing female taper gauges while the other is intended 
for testing male taper gauges. It will be seen that 






















374 


TOOLS AND PATTERNS 



there are three blades, A, which are set into a column 
of steel supported by a base, B. Along the blades, 
the limits for various sizes of tapers are marked, as 
indicated at C, D, E, F, etc. In use, then, a master 
gauge of this kind is set up on its base, the ring 
gauge is dropped over it, and an inspection will de¬ 
termine whether the ring gauge is made correctly 
both as to limit and proper taper. Gauges of this 
kind which are intended for reference only should be 
preserved very carefully and never used for anything 
except reference. 

Female Thread Gauges. —When a piece of threaded 
work, such as a shaft or stud, is to be gauged on its 
threaded portion, the testing is usually done by screw¬ 
ing the work into a female thread gauge, such 
as that shown in Figure 153. This gauge is made 
from a piece of steel of rectangular form and is 
drawn together or separated, as the case may require, 
by means of the set screws indicated at A and B. 





















INTERNAL, EXTERNAL AND THREAD GAUGES 375 


Adjustment is simply for the purpose of finishing the 
gauge to the correct size with as little difficulty as 
possible. It also provides a slight adjustment after 
the gauge has become worn. 

Gauges of this kind are seldom made with limits; 
but for very particular work two gauges can be used, 
one of the “go” variety and the other of the “not 
go.” For ordinary commercial work which does not 
require very close limits of accuracy a gauge of this 
kind will be found sufficient. 

For determining whether the lead of the thread is 
correct, a separate instrument must be used, as de¬ 
scribed in the next chapter. In general, threads of 
this kind are not gauged for the lead unless they 
are particularly important, in which case the in¬ 
dicating type of gauge is used to determine the cor¬ 
rect lead. 

There are other types of external and internal 
gauges which are used for special purposes, but the 
majority of them are modifications of those which 
have been shown or else they are of the indicating 
type of gauge for determining variations in inside 
or outside contours. The description of such of these 
gauges as are not mentioned in this chapter will be 
taken up in the following chapter. 


CHAPTER XXIV 


PROFILE AND INDICATING GAUGES 

Gauges for High Accuracy. —The present tendency 
in gauging methods is to do away as far as possible 
with all gauges which do not show the amount of 
variation in the work. Many of the gauges described 
in the previous chapter are made to indicate whether 
a piece of work has been finished within the required 
limits or not. The workman, in using ordinary limit 
gauges, has no means of knowing (except the sense 
of feeling) how nearly he is approaching the limits 
which are permissible. His first real knowledge that 
his tools have 44 gone the limit” is when his gauge 
tells him so. Hence it will be seen that for work 
requiring a high degree of accuracy, the ordinary 
types of limit gauges do not quite answer the pur¬ 
pose. For such conditions, then, some other type of 
instrument by means of which the actual variations 
in the work can be accurately determined, is essen¬ 
tial. 

Now let us see what principles can be used in 
gauging work, keeping it within the prescribed limits 
and at the same time indicating the variations which 
are taking place from time to time because of the 
wear and changes in size of cutting tools. It is evi¬ 
dent that indicating instruments which will show 
376 


PROFILE AND INDICATING GAUGES 377 

variations in the work make it possible for the work¬ 
man to change his tools as may become necessary 
and thus keep the work much closer to size than if 
the ordinary limit gauges were used. 

For instruments of this kind variations in the work 
can be shown by a pointer of some sort working over 
a graduated scale; by the sense of touch in the work¬ 
man’s fingers as they are passed over one or more 
movable points; or by the sense of hearing, as in the 
case of a gauge showing limits by an electric contact 
which rings a bell or operates a buzzer. Of these 
three types, the dial-indicating, or multiplying-lever 
type, is most common. This gauge has a sensitive 
movable pointer which works on a graduated scale or 
dial, and can be adapted to an infinite number of 
uses in gauging. The 66 feeler” or 66 flush pin” gauge 
is also used to a considerable extent on work of 
irregular form, or for depth gauging; it is sometimes 
found convenient to use it also in the case of deter¬ 
mining a correct shoulder distance. Micrometer 
gauges are also used to some extent on work requir¬ 
ing the highest degree of accuracy. And finally, 
there is a type of gauge which employs a delicate and 
sensitive arm so arranged that it multiplies the 
actual variation in a piece of work; if the variation 
is too great, it rings a bell by an electrical contact, 
or shows a red or green light if this scheme is pre¬ 
ferred. 

Standard Instruments of Precision.— Any mention 
of gauging systems which does not include some of 
the standard measuring instruments would be in¬ 
complete, but as we are for the most part concerned 


378 


TOOLS AND PATTERNS 



MICROMETER HEAD 


FIG. 154. MICROMETER GAUGES SHOWING CONSTRUCTION 
FEATURES 

with special gauges, we will not devote a great 
amount of space to instruments which are adapted to 
the most minute variations, such as micrometer and 
vernier calipers and other instruments of precision. 
But as the principles on which these instruments 
are based are also applied to gauging certain kinds 
of work, let us look into the fundamental points on 
which they depend for their accuracy. 

The micrometer caliper, shown in Figure 154, is 
familiar to all, and a brief description is all that will 
be necessary. The upper portion shows at A a gen¬ 
eral view of the instrument; a sectional drawing just 
below, gives an excellent idea of the construction. 
The frame, B, is a drop forging which is supplied 











PROFILE AND INDICATING GAUGES 379 

with a hardened inserted anvil, C. The frame is 
bored out and has an adjusting nut, K, inside and a 
short nut, L, to compensate for the wear on the 
threads. The screw, D, is threaded at E, and is fast¬ 
ened to the thimble, G, so that it can be rotated by 
the fingers of the operator. Each revolution of the 
screw moves it longitudinally 0.025 inches. The upper 
view shows the graduation on the thimble; and as 
there are 25 of these, starting with 0 and running to 
25, each division represents 0.001 inch. It will be 
seen that by placing the work between the points C 
and D and adjusting the screw by means of the 
thimble, an accurate reading can be easily obtained. 
This type of instrument is used all over the world for 
accurate measuring. The micrometer head shown in 
the lower portion of the same figure is sold as a 
separate instrument and can be applied to many 
forms of gauging by mounting it on a suitable fixture 
to conform to the work which is being gauged. 

Dial Indicator.—Another form of gauge, useful for 
inspecting a number of parts of the same kind, is 
shown in Figure 155. This instrument may be 
adapted to a variety of work by mounting it on a 
suitable holder to fit the conditions. It should not 
be considered as a gauge, however, but more as an 
indicator to show variations in size after setting it to 
a size block or plug. This instrument consists of the 
base, A, on which is erected a vertical shaft, B, 
absolutely perpendicular to the base. A sliding lever 
acts on this shaft as a holder for the dial indicator, 
C. The sleeve can be vertically adjusted and clamped 
at any desired height by means of a thumb screw 


380 


TOOLS AND PATTERNS 


F\ a 
VJi 

<r'B 


A 


ik 




FIG. 155. AMES DIAL TEST GAUGE ARRANGED FOR INSPECTION 
OF SHAFTS 


(not shown) at the rear of the instrument. The gauge 
point, D, is connected with the dial by means of a 
multiplying device inside of the instrument case, and 
the dial is graduated to read in thousandths of an inch, 
or finer if desired. In operation, a plug of the desired 
size, similar to that shown at G, is used for setting 
the gauge and indicator so that the pointer will read 
0 if the work is correct. A piece of work, such as 
shown at E, is then passed under the gauge point, D, 
and the reading is noted. Variations can be quickly 
determined in this way, and a number of pieces tested 
one after the other. Indicators of this type are also 
frequently mounted on special gauging fixtures for 
special work. 

Prestwich Fluid Gauge.—There has been a demand 
for many years for an accurate indicating gauge 
reading to one ten-thousandth part of an inch or 
finer, and a number of instruments are now on the 
market which will give readings as close as this, but 









PROFILE AND INDICATING GAUGES 


381 



FIG. 156 . PRESTWICH FLUID GAUGE 





382 


TOOLS AND PATTERNS 


they are quite delicate in construction and require 
careful handling as well as care in reading. 

The recently developed gauge shown in Figure 156, 
however, answers the demands of modern engineering 
work most admirably, and the reading of the instru¬ 
ment is so plain that a variation of one ten-thou¬ 
sandths part of an inch is discernible across an ordi¬ 
nary room. Furthermore the work can be gauged to 
specified limits, with the gauge set to meet the re¬ 
quirements of the work. 

For ball bearings, thread gauges, or any other work 
which needs to be calibrated in large quantities and 
within very close limits of accuracy, an instrument of 
this kind is indispensable. The principles involved in 
the construction are as follows: A fluid-containing 
chamber, A, is provided with a flexible diaphragm, 
B, and a glass tube, C, finely bored and connected 
with the chamber, A. The diaphragm, B, is furnished 
with a hardened steel pin or anvil, D, and the base of 
the instrument also has a fixed anvil, E, between 
which and the anvil, D, the work is passed when 
calibrating. The chamber, A, contains a colored 
liquid which rises and falls in the glass tube, C, 
according to the pressure applied to the anvil, D, and 
transmitted to the diaphragm. The large area of the 
diaphragm in comparison with the fine hole for the 
liquid in the tube makes possible such a fluctuation 
in the tube that it is easier to determine variations 
of a ten-thousandth of an inch with this instrument 
than it is to discern a thousandth with most other 
measuring instruments. The chamber, A, is provided 
with a thread and micrometer index and a pointer on 


PROFILE AND INDICATING GAUGES 


383 


the upper surface, as indicated, to show thousandths of 
an inch. This portion of the instrument is made for 
the purpose of obtaining rough adjustments; but it 
is not used after the instrument has once been set 
to the size desired. The carrier, F, is furnished with 
a scale, G, and three adjustable pointers, H, J, and K. 
The upper two of these pointers are so arranged that 
they can be set to indicate the tolerance limit between 
which it is desired to keep the work when gauging. 
The lower pointer, K, is set to the normal level of the 
fluid in the glass tube, C, so as to compensate for any 
fluctuations from changes in temperature. The in¬ 
strument is roughly set to the size desired by means 



fig. 156 -a. prestwich gauge used in gauging a piston 




































384 


TOOLS AND PATTERNS 


of the rack, M, and the pinion, N, on the pillar, 0, to 
suit the piece which is to be gauged. The clamping 
screw is then tightened, and the final adjustment is 
made by the micrometer dial, A, to a standard gauge 
or a piece of the given dimension. 

In the illustration, a piston wrist pin, X, is being 
gauged, a small special angle plate being set on top 
of the anvil, E, for this purpose, as clearly indicated. 
It is evident that a reading can be taken on a pin of 
this kind by simply pushing it along and noting any 
fluctuation in the column of liquid, C. 

Referring to Figure 156-A, the same type of gauge 



fig. 156-b. prestwich gauge used for inspection of 

THREAD GAUGES 


















PEOFILE AND INDICATING GAUGES 


385 


is shown applied to the measurement of an auto¬ 
mobile piston. In this case it will be noted that the 
base of the gauge is furnished with a special block, 
S, and that a different indicating point, R, is used. 

In testing a thread gauge, such as that shown in 
Figure 156-B, another application of this most useful 
gauge is found. In this case the indication point is 
of special form, permitting the “three-wire system” 
from the fixed diameter to be used. It will be seen 
that with this improvement, thread gauges or work 
of similar character can be determined with the 
utmost nicety and that the most approved system of 
gauging from the pitch diameter can be adopted. 
This gauge can be applied to many other varieties of 
special work, and its sensitiveness and facilities for 
quick and accurate reading make it invaluable to the 
progressive manufacturer. 

Flush-Pin Gauges.—The flush-pin gauge is with¬ 
out doubt the simplest type of gauge based on the 
indicating principle. Several applications can be 
made of this principle, one of the most useful of these 
being the measuring of depths or shoulders. 

Flush-pin gauges usually consist of a base or holder 
of some sort in which one or more pins are inserted 
so as to form a sliding fit in their bearings. The pins 
are made of correct length for gauging a given sur¬ 
face, the limit being determined by noting the amount 
of projection of the end of the pin beyond the end 
of the gauge itself. 

As an example, let us take the flush-pin depth- 
gauge shown in Figure 157. In this case, the work, 
A, is placed on a surface plate and the gauge is used 


386 


TOOLS AND PATTERNS 



to determine the correct distance, B. The gauge 
itself consists of a holder, C, through which the 
gauge pin, D, works, a small retaining pin being used 
to prevent the pin from falling out when not in use. 
The end of the gauge pin is cut away to the center 
line to show the amount of tolerance allowed in 
manufacturing the work. In using the gauge the in¬ 
spector simply notes that the shoulder on the pin is 
lower than the finished surface on the holder and that 
the end of the pin does not go below the shoulder. 
This indicates that the work has been machined 
within the desired tolerance. 

Gauges of this kind are not suitable for work 


















PROFILE AND INDICATING GAUGES 387 

within very close limits. From 0.003 to 0.005 inch is 
as close as this type of gauge can he used to advan¬ 
tage. When work permits a variation of 1/64 to 1/32 
inch, gauges of this kind are frequently used, but for 
the closer work they are by no means to be recom¬ 
mended. They can be adapted, however, to fine read¬ 
ings by using an indicator to act on the end of the 
pin. This indicator can either be of the dial type, 
applied by mounting it on a suitable holder, or it can 
be a simple pointer pivoted in such a way as to 
provide a large ratio of movement at the end of the 
pointer. 

Referring to Figure 158, let us -suppose that the 
push pin, A, in the upper sketch, is in contact with 
the work at the end, B, and that variations to 
0.001 inch are to be noted. If the short end of the 
pointer has a fulcrum % inch from the bearing, C, on 



FIG. 158. FLUSH-PIN GAUGE FOR PRECISE WORK 















388 


TOOLS AND PATTERNS 


the end of the pin, and the pointer is five inches long, 
then the ratio of multiplication will he as % is to 5 or 
as 1 is to 40. Therefore, if the graduations on the 
arm or scale are cut 0.040 inch apart, a variation of 
the pointer on one of these divisions will indicate 
0.001-inch variation on the push pin. 

Application of this principle can he made to many 
forms of gauges requiring a reading closer than that 
given by the ordinary flush-pin type. Still closer in¬ 
dications can he obtained by multiplying the levers, 
as shown in the lower portion of the diagram. One 
lever, E, working on another, F, will obtain a larger 
ratio. 

Flush-Pin Gauge for Tapered Shafts.—When a 

tapered shaft is close to a shoulder, as in the case 
shown in Figure 159, it is difficult to gauge the taper 
as to its position. In such cases, the flush pin, B, 
can be arranged so as to push the gauge on to the 
shaft until the pin strikes the shoulder, A, on the 
work, indicating the limit when the pin protrudes 



FIG. 159. FLUSH-PIN GAUGE FOR TAPERED SHAFTS 





















PEOFILE AND INDICATING GAUGES 389 

through the gauge at C. This pin is shouldered to 
indicate the permissible limit of error similar to that 
shown in Figure 157. Gauges of this kind can also 
be used for determining shoulder distances on straight 
or taper shafts. 

Flush-Pin Gauge for Contours.—In some instances 
it is desirable to gauge one or two points with con¬ 
siderable accuracy and other points not nearly as 
closely. Take, as an example, the work shown in 
Figure 160. In this case, the length of the work 



between the points F and G, is not of the greatest 
importance, but the irregular portions at B and C 
must not be above a certain dimension and can be 
permitted to be under the dimension by 0.005 to 
0.010 inch. The gauge in this case consists of a 
block, L, on which the pins, G, F, D, and E, are 
carefully set and against which the piece locates. Two 
flush pins, at H and K, are cut away on the end to show 
the amount of the tolerance permitted. It will be 
seen, then, that as the work is placed in the gauging 

















390 


TOOLS AND PATTERNS 



fixture these two pins, H and K„ can be moved up 
against the points B and C, and the inspector can 
easily determine whether the projection of the end of 
the flush pin is too great or not. In this way the 
desired contour of the work can be kept within the 
required limit. Applications of this principle may be 
made to many other kinds of work where it is neces¬ 
sary to keep a certain portion within a specified tol¬ 
erance. 

Flush-Pin Depth-Gauge for Indicating Two Sur¬ 
faces Simultaneously. —Another type of flush-pin 
gauge for use on two surfaces at the same time is 
shown in Figure 161. This gauge is made up some¬ 
what differently from the others, as the pins are 
made of flat stock and the holder is composed of two 
side pieces, with fillers between them, the two side 
pieces, D, and the fillers, E, being riveted together as 
indicated. The pins, A and B, indicate different 
depths on the fly-wheel casting, C, and the limits are 
shown by the shoulders on the pins, as indicated at 
F and G. 

















PROFILE AND INDICATING GAUGES 


391 


Where the work is large, as indicated in the illus¬ 
tration, a gauge of this kind may be preferred to one 
made of a solid piece of bar stock with holes drilled 
and reamed for the pins. It is somewhat lighter in 
construction and, although no cheaper to manufac¬ 
ture, it is a trifle more convenient to handle. Its 
operation is similar to the flush-pin gauges previously 
described. 

In making a gauge of this kind, the various parts 
are hardened and are lapped to a finish. Suitable 
retaining pins are inserted so that the gauge pins will 
not be lost when the instrument is not in use. 

Indicator Gauge for Testing Alignment of Con¬ 
necting-Rod Bearings. —The parallelism and align¬ 
ment of the connecting-rod bearings of an automobile 
motor is exceedingly important. It is not enough to 
know that the alignment of the bearings may be in¬ 
correct, but the amount and direction of variation 
must also be known. In order to determine these 
two points it is necessary to use a gauge based on 
the indicating principle. 

An excellent type of gauge for this purpose is shown 
in Figure 162. The connecting rod, A, has been pre¬ 
viously finished in all of its dimensions, and is sup¬ 
posed to be correct and ready for the final inspec¬ 
tion. Previous to placing the work in the gauge, it 
is fitted with the special pins, B and C, hardened 
and ground to size, and fitting closely in the bear¬ 
ings at each end of the connecting rod. After the 
work has been supplied with these two pieces it is 
placed in the fixture, T, in such manner that the large 
end of the connecting rod lies between the finished 


392 


TOOLS AND PATTERNS 



FIG. 162 . INDICATING GAUGE FOR TESTING ALIGNMENT 


































































































































































































PROFILE AND INDICATING GAUGES 


393 


surfaces, 0, on the fixtures and the pins at B and C 
rest on the hardened pins, D and F, at the large and 
small ends of the fixture respectively. When the 
work is placed in position the spring pins, N, hold it 
firmly against the hardened pins, E, the pins, N, being 
carefully adjusted so as to be perpendicular to the 
center line of the work. 

At the smaller end of the piece there is a fixed pin. 
F, and, on the opposite side, a pin, G, with an adjust¬ 
able knurled head and supported by the coil spring, 
H, in the body of the fixture. One side of the spring 
pin is slotted at K to receive the end of the indicator, 
L. This indicator works on a scale, M, reading to 
.001 inch. It can be seen, therefore, that any vari¬ 
ation in alignment of the connecting-rod bearings 
will be indicated by this pointer if the holes are not 
parallel in the direction indicated. 

Assuming that a discrepancy has been found in the 
alignment, a suitable clamp can be placed on the 
piece while it is still in the fixture and it can be 
twisted until the alignment is correct. Having 
straightened out the alignment in this direction, it 
is then necessary to gauge the work in another posi¬ 
tion. For this purpose the arm, P, bearing a dial in¬ 
dicator, S, is mounted in bearings, Q and R, these 
bearings being put on a line with the center line of 
the work. An indication of the parallelism of the 
shaft, C, with that of the other end, B, can easily be 
determined by swinging the indicating gauge, S, from 
one side to the other of the shaft, C, and noting 
whether there is any variation in the reading of the 
dial when this is done. The indicator should read 


394 


TOOLS AND PATTERNS 



FIG. 163. ELEVATION OF INDICATING GAUGE FOR AN AUTOMOBILE CAM SHAFT 































































PROFILE AND INDICATING GAUGES 


395 



FIG. 163- A. PLAN OF INDICATING GAUGE FOR AN AUTOMOBILE CAM SHAFT 
















































































396 


TOOLS AND PATTERNS 


the same on each side of the shaft if it is perfectly 
parallel with the other end. 

Applications of this type of gauge may be made to 
many kinds of work. It is possible to use either the 
dial indicator, as shown in this instance, or multiply¬ 
ing levers to indicate the amount of variation in the 
work. This particular gauge was designed by me on 
some work for the Russian government. 

Special Indicating Gauge for an Automobile Cam 
Shaft. —An automobile part requiring great care in 
gauging is the cam shaft. A special indicating gauge 
designed for such use is shown in elevation in Figure 
163 and in plan in Figure 163-A. In this work the 
shape of the cam and the amount of throw are the 
important points to be inspected. Usually the amount 
of throw of the cam is not permitted to vary more 
than 0.003 inch; some manufacturers hold their work 
within tolerances even closer than this. 

In the cam shaft, shown at A, the cams indicated 
at D, D, D, have been forged integral with the shaft 
and ground to the desired shape. An essential point 
connected with the form and throw of the cams is 
their location with respect to each other and also in 
relation to the keyway on the tapered end of the shaft 
at B. It follows, therefore, that the work should be 
located from this keyway in gauging the cam. The 
fixture itself consists of a base plate, K, which has 
been carefully scraped to a fine finish on the surface. 
On this base plate three bearings, E, are set, which fit 
the outside diameter of the cam shaft. In gauging 
the work the shaft is laid in these three bearings and 
swinging clamps are pulled down on top of the shaft 


PROFILE AND INDICATING GAUGES 397 

by means of the handles shown at F. As these 
handles are pulled down, the detent pins, H, snap into 
place in a conical hole in the side of the lever, and 
the spring plungers in the center of the swinging 
clamps, as shown at G, bear down on the cam shaft 
and hold it firmly in place in the bearings, E. 
Although these spring pins hold the cam shaft firmly 
in place they do not prevent its rotation. After the 
piece has been set into place, the finger lever, E, is 
pulled down until the work can be revolved suffi¬ 
ciently to permit the locater to enter the key way at 
B. The work is now set ready for gauging. 

Let us assume that the work has been placed in 
position and that everything is ready to indicate the 
piece. It will be noted that the block, L, is fastened 
to the bed plate of the fixture and that the finger 
lever, E, is contained in a sliding cylindrical piece 
held in position by an internal spring. At the end of 
the shaft, M (which works in a hardened bushing on 
the inside of the block, L), a dial plate, 0, is keyed 
in the correct relation to the finger lever and keyway 
at E and B. This dial plate contains four tapered 
bushings in proper relation to the keyway, B, and the 
work can be indexed by pulling out the taper pin, P, 
and turning the knurled hand-wheel, Q, for indicating 
the various cams. To indicate the throw of the cam, 
a special gauge—set on the stand, S, and having three 
feet of hardened steel, as shown at T, and an upper 
arm with indicating points at U and V for the 
“go” and “not go” limit of the throw of the cam— 
can be slid along the surface of the plate until the 
“go” and “not go” points on the gauge come in con- 


398 


TOOLS AND PATTERNS 



FIG. 164 . FEELER GAUGE FOR AN AUTOMOBILE CRANK SHAFT 












































































































































































































PROFILE AND INDICATING GAUGES 399 

tact with the cam, thus determining whether the 
throw is within the desired limits or not. After these 
points have been determined, the indicating dial is 
revolved and the next cam in rotation is similarly 
tested. 

The contour or shape of the cam is gauged by 
means of the block, W, which has a steel plate at X, 
formed to the coutour of the cam. It is obvious that 
this gauge is also moved along on the surface of the 
plate until it comes in contact with the cam so that a 
comparison can be easily made by the inspector. 

After the shaft has been completely tested, the 
entire mechanism of the indexing head is pulled away 
from the tapered end of the shaft until the lever, M, 
drops down into the recess on the shaft prepared for 
it. This holds the mechanism far enough back so 
that the cam shaft can be removed without difficulty. 
A gauge of this kind is somewhat expensive, but the 
results obtained by its use are most excellent. 

Feeler Gauge for an Automobile Crank Shaft. —A 
limit gauge, rather peculiar in its character as it is 
not really an indicating gauge and yet can be de¬ 
pended upon to hold the work within the prescribed 
limits of accuracy, is the crank shaft gauge shown in 
Figure 164. This instrument is used to determine the 
widths of the various bearings on the crank shaft 
and their relations to each other. One of the features 
of this gauge is that it can be used on the work 
while in process—it is not necessary to wait until after 
the crank shaft has been removed from the machine 
before testing it for accuracy. 

The gauge itself consists of a single hardened and 


400 


TOOLS AND PATTERNS 


ground shaft, D, having at one end a templet plate, 
E, which fits the center bearing of the crank shaft 
and is prevented from moving sideways by means of 
the plate, C, which is cut out to fit the bearing, as 
clearly shown in the end view. The other end of the 
gauge is also provided with a plate, cut out in like 
manner so that the operator may steady the gauge on 
the work and that it may have a correct location in re¬ 
lation to the axis of the work. In order to prevent the 
gauge from falling over sideways while the various 
bearings are being tested, a piece of sheet steel, M, is 
fastened to the shaft as indicated. 

Let it be assumed that the inspector is ready to 
test the crank shaft and that the gauge has been 
placed in position. It will be seen that the bushings 
lying between the spacing collars H and K, have each 
two plates or fingers, F and F 1 and G and G 1 , located 
one on each side of the bushings. Also the bushing 
at the end of the crank shaft and between the col¬ 
lars K and M has also a pair of feelers, L and L 1 . In 
testing the work, the feelers at these various points 
are swung by the operator’s fingers between the bear¬ 
ings. If the first feeler goes through without diffi¬ 
culty and the second does not, the inspector is ready 
to pass the work. After one end of the crank shaft 
has been tested the gauge is reversed and the other 
end is tested in a like manner, using the center bear¬ 
ing as the gauging point in each instance. After the 
crank shaft has been gauged in this way, it is abso¬ 
lutely certain that all the crank pins and bearings are 
in correct relation to each other within the prescribed 
limits. 


PROFILE AND INDICATING GAUGES 


401 


Although this type of gauge is somewhat out of the 
ordinary, it has proved successful in this kind of 
work. It is obvious that the greatest care must be 
used in making the instrument so that the various 
parts may have no more freedom than is absolutely 
necessary. 

Electrical Contact Gauge for Cams. —The use of 

electrical contact for determining variations within 
certain limits is well shown in Figure 165. Here, the 



work, A, which is to be tested, is a cam, the throw of 
which must be held within certain limits as in pre¬ 
vious instances. In this case, however, the cams are 
not on a shaft, but are separate and can be handled 
on a much smaller and simpler type of fixture. 

The work, A, is placed on a stud (not shown), the 
stud being located in the fixture plate. The gauge 
is so arranged that if the throw of the cam is cor¬ 
rect, a red light will show at J; while if the throw 





















402 


TOOLS AND PATTERNS 


of the cam is too great, the hell, K, will ring. A 
reference to the illustration will show that a battery 
is connected with the screw, F, and through it to the 
tempered spring, E. A multiplying lever, C, is 
pivoted at B, and acts on the push pin, D, which in 
turn pushes up the flat spring, E, until it is in con¬ 
tact with the adjustable screw, G. This completes an 
electrical circuit through the wiring indicated by the 
dotted line, and lights the red light at J. If the 
throw of the cam is too great, the push pin, D, forces 
the spring, E, up further until it touches the other 
screw, H, which also completes an electrical circuit 
and rings the bell at K. It must be understood that 
this is only a diagramatic illustration of the prin¬ 
ciples applied, and that various applications suitable 
to the particular piece of work which is to be gauged 
can be conveniently made. 

Profile Inspection Gauge. —On certain classes of 
work the profile of the piece must be kept within 
certain limits. It is not always possible or conve¬ 
nient to make up a receiver gauge for this purpose 
and even when one is used, the results obtained do 
not show up the variations markedly enough. 

The use of the ordinate principle can be employed, 
as shown in the Figure 166, in a case of this kind. 
This system of gauging leaves nothing to be desired 
where it is needful to inspect for accuracy and to de¬ 
termine, at the same time, the variation in the con¬ 
tour of the work. This gauge consists, first, of a sur¬ 
face plate, A, which has been carefully scraped to a 
plain surface. On this plate a master-gauge piece, X, 
is placed and fastened securely in position, and is 


PROFILE AND INDICATING GAUGES 


403 



FIG. 166. PROFILE INSPECTION GAUGE 

furnished with two dowels, D and E, on which the 
piece to be gauged is located. A dial indicator, F, is 
mounted on a special block, C, and has a hardened 
point, G, directly under the gauge or indicator point 
on the dial. Before using the gauge it is moved over 
to the plate, B, and the dial is set at 0, the pin then 
being in contact with the perpendicular side of the 
block, B. After the gauge point has once been set in 
line and the indicator turned around so that the dial 
around the work to the various lines shown until the 
lines on the indicator correspond to the lines on the 
base plate, A. A reading can then be taken, and if 
the pointer does not show variation greater than that 
marked on the plate at the point where the reading 
is being taken, it may be safely assumed that the 
work is within the limits prescribed. The system, of 
gauging can be applied to many forms of work which 
require a careful inspection of the contour and where 


















404 


TOOLS AND PATTERNS 



FIG. 167 . GAUGE FOR DETERMINING CONCENTRICITY 


it is necessary to know how much variation there is 
at various points. 

Concentricity Indicating Gauge for High-Explosive 
Shells. —In the inspection of high-explosive shells the 
concentricity of the exterior surface with the inside 
is important. In order to determine this rapidly and 
without difficulty, the gauge shown in Figure 167 
was designed. This is a very simple type of in¬ 
dicator gauge and the principles upon which it is 
based are applicable to many other forms. The 
work, A, is placed on the fixture and is located by the 
lower end, which is tapered, at C and also by means 
of the sliding tapered bushing at D. This latter 
bushing is supported by a light spring, E, in order 
to make sure that there is a contact on both tapered 
bushings. If this were not so arranged, it might be 
that the work would be placed in position and located 
only on one end, which would cause a wobble in the 



















PROFILE AND INDICATING GAUGES 405 

work when indicating. The standard on which these 
two bushings are located may be revolved in the fix¬ 
ture, and the work can be turned around freely by 
hand when in position. As the work is revolved, the 
plunger, F, which is spring controlled, bears against 
the outside of the casing and operates the indicating 
pointer, pivoted at K, and has a fulcrum at G. The 
lower end of the pointer moves along the arc of the 
graduated scale, H, thus showing variations in the 
concentricity of the work according to the amount of 
multiplication in the lever. In the case noted, the 
multiplication is 20 to 1, as this is amply sufficient 
to show variations in the concentricity of the work. 
The principle shown in this fixture can be used with 
an indicating dial; it is simply necessary to mount the 
dial indicator in some way on the fixture so that the 
push pin, F, will operate against it. 

Johansson Gauges.— Any description of gauging 
systems which does not include some mention of the 
testing blocks originated by Mr. C. E. Johansson 
would be incomplete, although the system is well 
known throughout the country. Briefly stated 
Johansson standard gauges are parallel-lapped blocks, 
in which the two opposite sides of each block are per¬ 
fectly parallel and the distance between them is equal 
to the size marked upon the block. These blocks are 
furnished in a number of sizes, so that any dimen¬ 
sion up to the limit of the various blocks can be 
obtained by placing the surfaces of blocks marked to 
the sizes required against each other in such close 
contact that a measurement across the blocks will 
give absolutely the dimension required. 


406 


TOOLS AND PATTERNS 


All Johansson standard-gauge blocks up to 6 inches 
are guaranteed to have no greater error than 0.00001 
inch, that is 1/100,000 part of an inch. They were 
originally intended for use in the tool room only for 
the quick and accurate laying out and checking of 
jigs and fixtures, but their applications have become 
better known until now they are used for checking 
many varieties of work. The gauge blocks are made 
up in a number of sets to suit various requirements. 
With their standard holders for making up a num¬ 
ber of blocks to a required dimension, they can be 
considered as a valuable adjunct to the tool room 
for checking dimensions, limits, gauges, and other 
work requiring extreme accuracy. A lengthy descrip¬ 
tion of the Johansson system of gauging is unneces¬ 
sary, but it is safe to say that no manufacturer who 
is engaged in the production of interchangeable work 
or any kind of work requiring extreme accuracy 
can afford to be without a set of these gauging 
blocks. 


CHAPTER XXV 


PATTERNS 

The Use of Patterns, —A casting which is to he 
machined must be made by a pattern. The simplest 
form of a pattern may be identical in shape and 
size with the piece which is to be made; but, on the 
other hand, the pattern may differ quite widely, 
depending upon the construction of the piece, the 
number of holes in it, and whether it has ribs or 
protuberances of different kinds which may necessi¬ 
tate that it be made up to provide for the use of 
core boxes or core prints. Speaking generally a pat¬ 
tern is a form which can be laid in damp sand or some 
other plastic material such that when molten metal is 
poured into the mold the desired shape will be re¬ 
produced in metal. Usually the outside of a pattern 
has the general form of the piece which is to be 
moulded and differs from that piece only in the 
various pieces called core prints, which stick out from 
the patterns here and there according to the require¬ 
ments of the work. 

Patterns are usually made of wood, but they may 
also be made of metal, rubber, plaster, and occa¬ 
sionally of other materials. Regardless of the ma¬ 
terial used, however, the pattern itself does not differ 
in form nor is the result obtained greatly different. 

407 


408 


TOOLS AND PATTERNS 


In work requiring a great number of pieces of the 
same kind, metal patterns are more commonly used, 
as they are more durable and will stand handling 
much better than the wooden. For work that is 
comparatively small and involving a number of 
pieces of the same kind, a number of small metal pat¬ 
terns can be made up and arranged in the mold 
about a “gate,” so that a great many castings can 
be made at one time in the one mold. 

Wooden patterns and metal patterns are made in 
practically the same way, the difference being that the 
metal pattern must be cut and worked into shape 
with different tools than those used on the wooden 
pattern as it is obvious that metal cannot be cut 
properly with wood-working tools. Frequently, in 
the making of a metal pattern, a wood pattern is 
first made which is a little larger than the work is 
to be, so as to allow for finishing and also for shrink¬ 
age, and a casting is made from it in some kind of 
metal which can be conveniently worked. This cast¬ 
ing is then used for the metal pattern after the pat¬ 
tern maker has worked it up to the desired size. 

Form of Pattern. —In making a casting, the first 
thing for the pattern maker to determine is just how 
his work is to be molded. The important point in 
this connection is the withdrawal of the pattern from 
the sand which has been rammed around it. If the 
pattern is simple in character, no great difficulty 
should be experienced in this matter; but if the work 
has a number of bosses or lugs and is of a peculiar 
shape, the matter of molding must be carefully con¬ 
sidered by the pattern maker in the making up of 


PATTERNS 


409 


his patterns. Obviously, it is necessary for the pattern 
to be made in such a way that the molder can with¬ 
draw it from the sand without disturbing the im¬ 
pression which the pattern has created in the sand. 
The pattern maker must always possess foresight 
enough to make provision for removing the pattern 
from the mold after the sand has been packed 
around it. 

Method of Molding.— The best way to understand 
thoroughly just how a pattern is molded is to describe 
the process in connection with a simple pattern, such 
as that shown in Figure 168. In the first place 
it must be recalled that the fine sand used for mold¬ 
ing is moistened slightly so that it will hold together 
in the flasks into which it is pounded or rammed 
around the pattern. These flasks are of various 
kinds, but in their simplest form they are boxes open 
at top and bottom and made either of wood or metal. 
The boxes are provided with lugs on the sides 
through which dowel pins may be passed so that two 
flasks can be put together in such a way that they 
always bear the same relation to each other. They 
can then be separated and replaced at will, with the 
assurance that the parts of the mold m the sand will 
correspond. The upper half of the flask is he 
“cope” and the lower half is the “drag” or “nowel. 

It will be noted that the pattern shown at A m 
Figure 168 is what may be called a “solid” or “one 
piece” pattern and that it has no core in it It may 
be said of this pattern, therefore, that it leaves its 
own core in the sand and does not require anything 
special in its construction. This particular piece is 


410 


TOOLS AND PATTERNS 


an exact model of the casting which it will produce 
and is a good example of the simplest form of mold¬ 
ing. The shape of this particular piece is such that 
the angles on both outside and inside give an excel¬ 
lent draft, permitting the work to be removed with¬ 
out disturbing the sand in any degree. When the 



FIG. 168 . METHOD OF MOLDING A SIMPLE PATTERN 

molder prepares to mold this pattern he takes a large 
flat board, such as that shown at C, and places it on 
his bench. On this board he places the pattern, A, 
with the large side down; over it he puts the drag 
portion of the flask. He then sifts or “riddles” fine 
sand all over the surface of the pattern and rams it 
tightly. After this has been done, he fills the re¬ 
mainder of the flask with coarse sand which is also 
rammed tightly, just filling the box flush to the top. 













PATTERNS 


411 


The entire box is then turned over until the cope side 
comes upward, as shown in the illustration. The ex¬ 
posed surface is now sifted or covered lightly with 
parting sand—that is, white beach or river sand. 
This is done to prevent the cope side of the flask from 
sticking to the drag. The cope side is then placed in 
position over the drag and the entire box filled with 
coarse sand, rammed in. Cope and drag are then 
separated, the pattern carefully removed from the 
mold, the cope replaced, and the flask is ready for 
molding or is set aside until required. 

Cores and Core Boxes. —If the casting to be made 
requires a hole in it and, because of the shape of the 
pattern, it is not possible to place the pattern in the 
mold (as in the instance noted) in such a way as to 
leave a pyramid or conical portion of sand in the 
mold that will prevent the metal from flowing into 
that part and thus leave a hole in the resulting cast¬ 
ing, it will be necessary to make a separate “core.” 
For example, in Figure 169 a separate core is neces¬ 
sary on account of the shoulder on the inside of the 
work. This requires that a core box be made 
specially for it. 

Cores may be made from metal, dry sand, or green 
sand. The kind illustrated in Figure 168 is the green 
sand core and is made at the same time that the 
mold is made. There are occasional instances when 
a green sand core can be made up separately and 
placed in the mold, but these cases are rather rare 
and need not be considered here. Metal cores are 
chiefly used in brass work or other work in which 
considerable accuracy is required. They are not used 


412 


TOOLS AND PATTERNS 



FIG. 169 . MOLD AND PATTERN SHOWING USE OF BAKED CORE 


in molding cast iron. The most common form is the 
dry sand core. This is made from a fairly coarse sand 
mixed with some binder material to hold it together 
and then baked until perfectly hard and thoroughly 
dry. 

Dry sand cores are molded in core boxes made np 
to the shape and size desired. Core boxes are usually 
made of wood in two or more parts, depending some¬ 
what on the shape of the core itself. The making of 
core boxes for patterns is fully as important as the 
making of the pattern itself. 

After the core box has been made, the mixture of 
sand, with the binder thoroughly incorporated in it, 
is placed in the core box until it is filled completely. 





























PATTERNS 


413 


It must be remembered that the core in the box is 
stable, but when removed it is somewhat delicate. In 
some cases, then, it is necessary to reinforce the core 
sand by means of rods or bars of different shapes to 
conform to the size of the core and its contour. After 
the core box has been filled, the core is removed, laid 
on a plate, and placed in the oven in order to dry 
out. It is then ready for use in the mold, having first 
been given a coating of blacking with a composition 
of plumbago or graphite, in order that the molten 
metal may not stick to the core. 

Referring to the pattern, A, Figure 169, a core 
print, as it is termed, is seen at each end. There is 
a taper on the upper of these prints, for it is on the 
cope side of the mold and the cope could not readily 
be removed unless this part of the print were made 
tapering. Occasionally the tapered end of the core 
print is removable, so as to make it easier for the 
molder to do his work. Otherwise the molder will 
bore a hole in his molding board to accommodate this 
end of the print when ramming up the pattern. 

Referring to the casting, B, shown in the same illus¬ 
tration, an inside recess is seen of such a form that it 
would be impossible to mold the work from a pattern 
without a separate core. Therefore a core box is 
made up to give the form indicated at C, and after 
the pattern A has been rammed in the mold, this core 
C is inserted prior to the molding operation as in¬ 
dicated in the illustration. When the metal is poured 
into the mold it will flow all around this core and 
into the depression left by the pattern form, thus pro¬ 
ducing the desired shape. After the iron has cooled 


414 


TOOLS AND PATTERNS 


and the mold is dumped, the core, being of a fragile 
nature, can easily be broken up and knocked out of 
the casting, which is then left in the condition shown 
at B. 

Two-Part Pattern and Method of Molding.—The 

casting, A, Figure 170, is seen to have flanges at 
each end of such form that the casting could not be 
molded in the same manner as that shown by Figure 
169. In work of this kind the better method is to make 
up a two-part pattern, as shown at B, and prepare 
to mold the work as indicated in the illustration. It 
will be noted that this two-part pattern is separated 
on the center line and that there is a dowel pin, C, 
at each end of the pattern so that the two parts can 
be placed together in their correct relation at all 
times. 

In molding, one-half of the pattern is laid down on 
the molding board and the drag portion of the mold 
is rammed up around it. The mold is then turned 
over and the other half of the pattern laid on to its 
fellow, after which the cope side of the mold can 
be rammed. After lifting out the pattern and placing 
the core in position as noted, the work is ready for 
molding. 

Occasionally in cheap pattern work it may not be 
desirable to make a two-part pattern. When this is 
the case, the method shown in the lower part of the 
illustration can be used. In this, the pattern is made 
in one piece, and the molder lays the pattern down 
on his molding board and rams up the mold in the 
drag portion. He then turns over the drag, as indi¬ 
cated in the illustration, cuts down the slope, D, 


PATTERNS 


415 



FIG. 170. TWO METHODS OF MOLDING A PATTERN WITH FLANGES 
Upper figure shows the split-pattern method. Lower shows 
solid pattern. 


with his molding tool, and removes the sand down to 
the center line of the pattern, leaving it all clear and 
clean. After sifting parting sand on the drag portion 
of the mold, he places the cope flask in position and 
rams this up also until it takes the form shown in 
the illustration. The cope can then be lifted care¬ 
fully off so as not to disturb the sand which is hang¬ 
ing below it, and the pattern can be removed and the 
core inserted as in the previous instance. This 













































416 


TOOLS AND PATTERNS 


method of molding is seldom used unless only one or 
two castings are desired from a certain pattern, for 
too great a portion of the molder’s time is taken up 
than the work warrants. 

Circular Cover Pattern. —Figure 171 shows a some¬ 
what different type of pattern. Here the work to he 
produced from the pattern is shown at A, and the 
method of molding the piece is indicated in the .lower 
portion of the figure. In this case the parting line 
of the pattern is at C; there is a projection into the 
cope of the pattern itself, and also the portion, B, 
of the cope extends down into the pattern. To use 
this pattern it must be laid down on the molding 
board and a suitable recess provided for the flange 



FIG. 171 . CIRCULAR COVER PATTERN SHOWING PART OF THE 
MOLD IN THE COPE SIDE 


















PATTERNS 


417 


portion so that the parting line, C, will lie flat on 
the board. The sand is then rammed around the 
pattern, after which the drag is turned over in the 
usual way and dusted with parting sand. The cope 
is now placed in position and rammed up, the sand 
being forced down into the portion B, and lifting out 
as the cope is removed so that the part, B, remains 
hanging from the cope side of the mold. 

Pattern Requiring a Three-Part Flask. —In some 
instances it is necessary to mold a certain kind of 
pattern in a flask containing more than two parts. 
An instance of this kind is shown in Figure 172 
where the work, A, is a casting having four ribs and 
a flange at each end. It is apparent that it would not 
be possible to ram sand all around the pattern and 
then be able to remove it from the sand without dis¬ 
turbing the mold. The pattern is made up, therefore, 
in the form shown at B, the usual core print being 
applied and the pattern itself being arranged so that 
it can be separated along the line X-Y. 

The process in molding this pattern is,as follows: 
The large flange is placed on the molding board, the 
“ cheek” of the three-part flask is first rammed up as 
far as the separation of the pattern X-Y, the cope 
being then placed in position and rammed in turn. 
Both cope and cheek are then turned over together 
on to the molding board and the drag side is com¬ 
pleted. In removing the pattern, one part is drawn 
from the large flange side and the other from the 
small flange side. The core can then be placed in 
position in the usual way, and the mold is ready for 
pouring. 


418 


TOOLS AND PATTERNS 



FIG. 172. EXAMPLE OF MOLDING A FLANGED AND RIBBED PATTERN 
IN A THREE-PART FLASK 

Other Forms of Patterns. —It is not necessary to 
present a lengthy discussion of the various forms of 
patterns, hut several other kinds may be mentioned 
in a general way in order to make the subject a little 
clearer. The matter of loose pieces is one which occa¬ 
sionally gives the pattern maker and molder more or 
less trouble. For instance, in making a casting that 
has a number of lugs or bosses on it of such a kind 
that they could not be readily removed from the 
molds, the pieces are frequently made loose with a pin 
in them to permit their ready removal. In molding 






































PATTERNS 


419 


such a piece of work the pins are removed from the 
loose pieces before the pattern is taken out of the 
mold; the pattern can then be removed without dis¬ 
turbing the loose pieces which can be taken out by 
the molder’s hands afterwards. 

The type of patterns known as “sweep” patterns 
should also be mentioned. These are used for circular 
work when a very cheap pattern is desired. They 
can be made for almost any kind of cylindrical ring, 
and if made in sectional form to take up a certain 
portion of the mold desired, this part of the pattern 
can be attached to a radius stick pivoted at the cen¬ 
ter of the mold and a part of the mold rammed up at 
a time. After one section of the mold has been pre¬ 
pared in this way, the sweep can be moved, around to 
another section which is treated in like manner. 

Skeleton patterns may also be used in a somewhat 
similar way. But attention should be called to the 
fact that each of these types just mentioned is used 
for the purpose of economy where only a very few 
castings are to be made from any one pattern. The 
skeleton pattern is used in place of a complete pat¬ 
tern, but its principal claim to distinction is that it 
can be made up cheaply for cylindrical work. While 
the pattern maker saves considerable time in making 
either a skeleton pattern or a sweep, the molder, how¬ 
ever, is required to spend very much more time in 
making up the molds than he would do if he were 
provided with the proper kind of pattern. 

Tools for Pattern Making. —The tools used in pat¬ 
tern making are much the same as those used by any 
carpenter, except that a number of varieties of spe- 


420 


TOOLS AND PATTERNS 


cial tools are required, such as those used by the 
cabinet-maker and wood-carver. A number of spe¬ 
cial machines are in use in the pattern shop in order 
to facilitate the work of pattern-making. These in¬ 
clude such special machines as the core^box machine, 
which is specially designed to assist in cutting out 
the inside work in a core-box, and also sand-paper¬ 
ing machines of the disc type with adjustable tables 
to permit them to be set to different angles for the 
greater convenience of the pattern maker. Other 
tools used in the pattern shop are the circular saw, 
the band saw, the hand jointer or buzz planer, the 
mortiser, and the shaving machine. Special pattern¬ 
maker’s vises might also be mentioned, which are so 
constructed as to hold the work in any desired posi¬ 
tion without injury. The tool-maker’s engine lathe 
is also found in the pattern shop and is largely used. 
In addition to all the above, each pattern maker has 
his own private supply of hand tools, most of which 
have been made up by himself for certain kinds of 
work which has been out of the ordinary. Aside from 
these, the cabinet-maker’s or carpenter’s kit of tools 
would represent general usage. 


CHAPTER XXVI 


PATTERN RECORDS AND STORAGE 

Desirability of Pattern Records. —Keeping patterns 
after they are made, in a safe and readily accessible 
place, is a matter that has deservedly received con¬ 
siderable attention in late years. Formerly, the boss 
pattern-maker had a system of his own; he located 
any desired pattern in from ten minutes to three or 
four days, depending on his memory and the amount 
of time he could spare in looking it up. 

The boss pattern-maker frequently was, and still is, 
a man who had held the position for a number of 
years and who might be expected to know what a 
given pattern looked like and where it was likely to be 
found. Memory is a poor thing to depend on, however, 
for locating anything, and the results from the sud¬ 
den death, illness, or resignation of the man having 
this store of knowledge can well be imagined. Con¬ 
sider the amount of time consumed by the boss pat¬ 
tern-maker under ordinary circumstances in finding 
a given pattern and estimate the cost of finding the 
pattern under these conditions. 

However, it is gratifying to note the progress 
made in this respect among present-day manufac¬ 
turers. Nearly all of them now-a-days have a well- 
ventilated, light, and convenient pattern-storage 
421 


422 


TOOLS AND PATTERNS 


building, with suitable racks or compartments in 
which the patterns are kept. In former times it hap¬ 
pened not infrequently that the loft (if there hap¬ 
pened to be one above the pattern shop) was utilized 
for storage, and it took a man with a searchlight 
and a pair of good eyes some time to find what he 
wanted. 

Quality of Patterns. —Before going into the matter 
of pattern storage and records, I should like to say 
a few words in regard to economy in the construction 
of patterns; for it is always a good plan to consider 
other things in addition to the first cost of a pattern, 
and there are many factors affecting the construc¬ 
tion. 

It is obvious that the number of pieces to be made 
from a given pattern is an essential factor in deter¬ 
mining the character of the pattern. For example, 
a jig or fixture pattern is usually made as cheaply 
as possible, for it will only be used once or twice. 
Any other sort of pattern for a special machine or 
mechanism, which will be used for only one or two 
castings, would therefore seem to come under the 
same category, but here other factors vitally affect 
the construction. A special machine may be de¬ 
signed for use in a manufacturer’s own shop, or it 
may be sold to a customer; in either case the appear¬ 
ance of the finished machine must be considered, and 
therefore the pattern should be well filleted, with 
corners rounded, and finished throughout so that the 
castings obtained from it will be of good appearance. 

Speaking generally, it is not necessary or even de¬ 
sirable to give patterns of this kind a high finish 


PATTERN RECORDS AND STORAGE 423 

with several coats of varnish. A good sandpaper 
finish is usually sufficient, although a coat of shellac 
is a very good protective covering that may preserve 
the pattern in better condition than if it were left 
without it, in the event that other castings may be 
wanted at a later date. These matters are generally 
left to the judgment of the pattern-maker when he is 
instructed by the foreman as to the kind of pattern 
wanted. 

Usually in making a pattern for a single casting, 
the warping of the wood from which it is made and 
the consequent distortion arising therefrom are not 
taken into consideration, so that if another casting 
is desired at a later date, it may easily happen that 
the results obtained in the second case are unsatis¬ 
factory. If there is a likelihood of a pattern being 
used a second time, provision should be made to pre¬ 
vent undue warping. However, attention to this mat¬ 
ter should not permit too great an addition to the 
first cost of the pattern. Judgment should be used 
in all cases. 

Patterns which are built up in sections, with the 
grain of the wood running in opposite directions, are 
not generally desirable for single casting work on 
account of the first cost of the pattern; but when the 
shape of the work is such that there is strong likeli¬ 
hood of distortion, the pattern should be made sub¬ 
stantial enough to counteract any tendencies of this 
kind. 

For patterns which are to be used over and over 
again, the first cost should be a secondary considera¬ 
tion. A poorly built pattern will go out of shape and 


424 


TOOLS AND PATTERNS 


become so damaged by frequent molding that it will 
soon need to be replaced by another. Of course, 
when the size of the work will permit it, and the 
number of castings to be made warrants the expendi¬ 
ture, a metal pattern is most satisfactory. The cost 
of a metal pattern, however, is very much greater 
than the cost of one made of wood, so that it is un¬ 
economical to use metal unless a great many pieces 
of the same kind are to be cast from the same pat¬ 
tern. 

In machine-tool patterns there is always a pos¬ 
sibility of a change in design of the machine. This 
may make an entirely new pattern necessary, and 
therefore metal patterns should be rather sparingly 
used for work of this kind because of their expense 
and the likelihood of an early discard. 

Economy in Combination Patterns. —In the making 
of pulleys or gears with spokes, which require sev¬ 
eral pieces of the same diameter but with different 
lengths or sizes of hubs, considerable economy can 
be effected by using one spider and ring pattern with 
loose hub pieces of different lengths and diameters. 
A combination of these loose hub pieces with the 
spider and ring will meet a number of different con¬ 
ditions. The spiders can also be made with a vary¬ 
ing number of spokes and the pulley rings can be 
made in different widths so that a wide variety of 
castings can be obtained. Hubs and spiders can be 
so made as to be interchangeable one with another, 
so that with only a few complete patterns combina¬ 
tions of all kinds can be quickly and satisfactorily 
effected. 


PATTERN RECORDS AND STORAGE 


425 


Gear Molding Machine. —Another great economy 
in pattern making has been the development of the 
gear molding. This permits a special pattern to be 
made in sectional form which has only one tooth 
space on the rim and a part of a tooth on each side, 
instead of an entire pattern of a gear with teeth all 
around it more or less accurately spaced according 
to the skill of the pattern maker. The gear molding 
machine takes the sectional pattern and molds the 
remainder of the teeth far more accurately than is 
possible in any other way. 

Pattern Records, —Having considered the making 
of the patterns and the economies which can be put 
into effect in their construction, let us see how we 
can best take care of them after they have been 
made, and how we can locate them when wanted 
without resorting to memory. It is apparent that 
any record for patterns must be based on the method 
used in identifying any component part in the class 
of work being manufactured. Thus, if machine tools 
are being made, the system used should identify the 
machine by number or name, the part by number and 
name, and the location of the pattern in its rack in 
the pattern storage building. It is useful also to 
have the date that the pattern was made, its cost, 
and the weight of casting incorporated in the index, 
together with information regarding core boxes and 
a record of castings made with date of order, etc. 
Figure 173 shows a simple index card that is ap¬ 
plicable in recording the patterns used in making 
machine tools. 

In any record of this kind the cards should be filed 


426 


TOOLS AND PATTERNS 


Machine No_, Piece No_ 

Name of Piece _ Location_ 


Patterns_ L _ Core Boxes_&. 


Date Cast’gs Ordered 

No. 

Where Ordered 

Weight 

Price 

Cost 

7 - /2* - /6 

/6 

M.73. (£<?. 

/or* 

S 

fV 

//> 

S 

i 

i 

N 

SO 

?97/. 73. 

3/70 

si 

/7¥ 

dS 

i 

* 

i 

\s> 

>£ 

m,. 73. 



/4/S 




















































FIG. 173. PATTERN STORAGE RECORD CARD 


under the number of the machine itself and then 
numerically by piece number. A cross index is also 
valuable in which the parts are filed alphabetically 
by name, but this index need only be used when the 
piece number is not known. 

It is evident that any kind of a pattern storage 
index must be arranged according to the require¬ 
ments of the particular product, but adaptations of 
the foregoing system can be devised. 

Marking the Patterns. —Every pattern should have 
a number fixed to it so positively that it cannot be¬ 
come lost or separated from the pattern itself. An 
aluminum plate with the number embossed on it is 
very excellent for this purpose, and machines adapted 
to the marking or stamping of these plates should 
form a part of every pattern shop equipment. These 




























PATTERN RECORDS AND STORAGE 427 

machines are simple, reasonable in price, and do not 
get out of order easily. In addition to the number 
plate, the number should be painted on the pattern 
in case the plate should be knocked off and lost. It 
is also necessary to have the storage location plainly 
marked on the pattern, so that when it is returned 
from the foundry it can easily be put in its proper 
place without reference to the card index. 

Storing the Patterns. —The actual method used in 
storing patterns is dependent upon the facilities pro¬ 
vided or available for the purpose. If a building can 
be used for this storage, it should be equipped with 
steel or wooden racks—preferably steel laid out in 
aisles or sections. Each section can be given a letter 
and each shelf a number, so that a location specified 
as F-21, for example, would mean Section F, Shelf 21. 
This can be further subdivided to provide for small 
patterns by a suitable box which can be placed on 
the shelf and also designated by a number or letter, 
as F-21-C, which would indicate Section F, Shelf 21, 

Box C. .... 

The lighting of the pattern storage building is im¬ 
portant. If the building can be lighted by ordinary 
daylight, it is an advantage; but if daylight is not 
available, good artificial lighting should be provided, 
preferably by means of portable incandescent bulbs 
suitably caged and having long cords to permit lights 
to be carried from one shelf to another as required. 

Another point which should be mentioned in con¬ 
nection with pattern storage is that the building 
must be dry, since moisture is very apt to affect the 
glue in the patterns to such an extent that it may 


428 TOOLS AND PATTERNS 

cause them to fall apart and give an endless amount 
of trouble. 

By no means the least important of the factors in 
connection with pattern storage is the nature of the 
building in which they are stored. It might be said 
that above all buildings in the plant, this should be 
as nearly fireproof as possible. One can readily 
imagine the havoc caused to any plant through the 
loss of the patterns on which the business was based. 
At a price, buildings and machinery can be readily 
replaced in fairly short order; but patterns, which 
are the fruits of years of development and upon each 
of which large sums of money, in many cases, have 
been expended, can only be replaced, if ever, by an 
equal expenditure of time and money. In other 
words, it is possible that the loss or destruction of the 
patterns through fire might result in the total failure 
of the business; the least effect is a more or less pro¬ 
tracted delay in filling orders. 

Many of the patterns themselves are highly in¬ 
flammable; these should be individually guarded. 
Metal patterns, of course, suffer little danger of dam¬ 
age from a small fire; but in the event of the loss of 
the storage building by fire, even they would be dam¬ 
aged beyond repair. Too great stress, therefore, can¬ 
not be placed on this point, and in far too many cases 
it is a factor which has apparently been entirely 
overlooked. 


CHAPTER XXVII 


CARE AND STORAGE OF CRUCIBLES 

Clay Crucibles.—The crucibles used for melting 
small quantities of metals are made either from clay 
or graphite. In the steel industry crucibles are used 
extensively, principally in the manufacture of so- 
called crucible steel. Their greatest use, however, 
is in brass foundry work, and the graphite form is 
much preferred to the clay on account of its greater 
durability. 

When clay crucibles are used, a high grade clay 
is mixed with about 5 per cent of powdered coke and 
made into a stiff dough or paste by the addition of 
water. The mixture is then thoroughly worked or 
kneaded until it is of uniform consistency, after 
which it is forced into a mold of the desired shape 
by means of a plunger. The top of the crucible is 
then formed (after removal from the original mold) 
by forcing over it another die of conical shape. The 
formed crucibles are then allowed to dry slowly for a 
few days without the aid of artificial heat. After this 
preliminary drying they are placed near the melting 
furnaces for final drying out. 

In the molding operation a hole is left in the bot¬ 
tom of the crucible, through which a pin passes to 
center the plunger used in forcing the clay into the 
429 


430 


TOOLS AND PATTERNS 


mold. This hole is left open until the crucible is 
placed in the furnace, and is closed by resting it on a 
little clay stand in the furnace and throwing a little 
sand into the hole. This sand fuses very quickly from 
the heat, effectively stopping the hole and at the 
same time cementing the crucible to the stand on 
which it rests. 

The greatest care is necessary in handling clay 
crucibles. They must be heated very slowly, and 
must be re-charged while hot. While their normal 
cost is not high, they are easily broken and may 
cause a loss in metal and in damage to the furnace 
in which they are used far in excess of the value of 
the crucible. 

Graphite Crucibles.—Graphite crucibles have many 
advantages over those made from clay, and are there¬ 
fore used by a majority of manufacturers in this 
country. They will stand more heats and rougher 
handling than clay crucibles; can be tested for cracks 
and thickness before charging, and can be charged 
cold. 

Prior to the war, graphite crucibles were made from 
German clay and water to which is added sand and 
Ceylon graphite. A substitute for the German clay, 
however, is now being used which gives exceedingly 
satisfactory results. The mixture of clay, water, 
sand, and graphite, is made up into, a stiff paste 
which is allowed to “season’’ by keeping it in a damp 
place for several days. When the material has been 
properly tempered or “seasoned” it is placed in a 
mold upon a potter*s wheel and revolved. A movable 
arm or profile iron spins out the material to fill the 


CARE AND STORAGE OF CRUCIBLES 431 

mold, at the same time acting as a gauge to keep the 
walls of the crucible at the desired thickness for the 
purpose in hand. 

After the spinning operation, the crucible is sea¬ 
soned for another 24 hours at a temperature of not 
more than 80 degrees Fahrenheit, and is then 
smoothed up to its desired form ready for the final 
seasoning. This final seasoning is accomplished by 
keeping the crucibles at a temperature sufficient to 
drive off the hygroscopic moisture for a period of 
three weeks. They are then placed in an annealing 
oven at a temperature of 1500 degrees Fahrenheit and 
kept there for three days to remove all traces of 
moisture. This process is termed “burning”. The 
finished crucibles are then protected by placing them 
inside clay molds to prevent oxidation and damage of 
other kinds. Before using the crucibles, however, 
they should be kept for a considerable time in a warm 
place. This final seasoning tends to toughen the 
crucible and give them greater durability, hence they 
are often kept for some time after being made. Cru¬ 
cible covers are generally made from the bottoms of 
old pots, and are treated in the same way as the cru¬ 
cibles themselves. 

The “scaling” or flaking, which is sometimes seen 
in crucibles, is caused by improper annealing and 
seasoning. The material of which they are made is 
of such a nature that it absorbs moisture rapidly, un¬ 
less prevented, and when the crucible is placed in the 
furnace in this condition the moisture is converted 
into steam, causing a “flaking” V blowing off pieces 
of the pot entirely, thus rendering it unfit for use. As 


432 


TOOLS AND PATTERNS 


pointed out, the moisture must be driven off by a 
slow process of annealing and tempering in order to 
prevent any trouble of this kind. Crucibles which 
have been thoroughly dried out will seldom flake or 
crack when heated, and it is therefore of supreme 
importance to see that this preparatory work is 
thoroughly done. 

Storage of Crucibles.—The prime requisite in 
the storage of crucibles is that they be kept in a 
warm and dry place. Where pit furnaces are used 
in the foundry, an excellent place for storage is just 
back of the battery of furnaces, where both dryness 
and warmth will be assured. 

A special oven can be arranged which utilizes the 
waste heat from the furnaces, and by using dampers 
of suitable form the heat can be regulated to make 
an annealing oven of it. Whatever arrangement is 
made for crucible storage it is absolutely essential 
to provide continuous warmth, and not have an in¬ 
terval during which the crucibles cool off and ab¬ 
sorb moisture. 

Care in the Use of Crucibles.—An important point 
in connection with the care of crucibles is to prevent 
the graphite from burning off the outside of the pots 
during use. An oxidizing atmosphere will do this. 
Therefore when oil and gas furnaces are used for 
heating, a reducing flame must be kept up. A badly 
burned crucible is the result of directing an oxidiz¬ 
ing flame directly upon it; such a crucible is soon 
ruined. Better results will be obtained by using a 
wider flame from burners adapted to high-pressure 
oil and low-pressure air; these burners are more 


CARE AND STORAGE OF CRUCIBLES 433 


easily controlled and not so severe in their action as 
burners which are designed for low-pressure oil and 
high-pressure air. 

In using fuels, those which have a high content of 
sulphur form sulphur dioxide, which is very injuri¬ 
ous to crucibles. Such fuels, therefore, should be 
avoided. 

Crucibles will last much longer if the metal is 
poured as soon as possible after the proper tem¬ 
perature has been reached so that they will not be 
subjected to the burning action of the flame any 
longer than is needful. The life of crucibles continu¬ 
ally kept at high temperatures is comparatively 
short. It is of advantage, therefore, to use a crucible 
first in melting alloys requiring high melting 
points, then, as it grows older, prolong its life by 
melting alloys requiring a lower melting point. It is 
necessary, of course, to clean out any alloy of one 
kind thoroughly before using the crucible for another 
alloy, in order to prevent hybrid mixtures. No mat¬ 
ter what melting points are used or what alloys 
are melted, care must be taken in charging the pot 
not to crowd it full of scrap or heavy ingots of metal, 
as the expansion of these in melting is sometimes suf¬ 
ficient to crack or otherwise shorten the life of the 
vessel. 

Crucibles will have longer life in round furnaces 
than in square ones, because the heating is more uni¬ 
form in the former. For this reason tilting furnaces 
are easier on crucibles than pit furnaces. In using a 
pit furnace the life of a crucible is prolonged by plac¬ 
ing it in the furnace to cool gradually with the fur- 


434 


TOOLS AND PATTERNS 


nace rather than to let it cool in other atmosphere 
and under various conditions. 

A protective paint or a wash made of pulverized 
carborundum fire-sand mixed with water glass or 
boric acid, has a resisting effect and prolongs the life 
of a crucible to some extent. A coating of this kind 
has been used sucessfully in Europe and has recently 
been put on the American market. 



INDEX, 


Abrasives, Artificial, 97 

Adaptable Fixture for Grinding Spur 

Gears, 248 

Adjustable Boring Tool for Tool- 
Room Work, 48 

—Counterbalance for a Face-Plate 
Fixture, 175 

—for Grinding Bevel Pinions, 250 
—Turning Tool with Roller-Back 
Rests, 59 

Adjusting Nut, Expanding Arbor for, 
188 

Air-Operated Chucks, 130 • 

Allowance, Definition of, 349 
Aluminum Casting, Fragile, Vertical 
Boring-Mill Fixture for, 228 
—Thin, Fixture for, 169 
Aluminum, Lubricants for Cutting, 293 
Ames Dial Test Gauge, 380 
Angular-Generating Attachment for 
Vertical Turret Lathe, 216 
—Cross-Slide, 208 
Angular Milling Cutters, 79 
Angular Milling, Fixture for, 147 
Arbor, Definition of, 181 

—Expanding, and Faceplate for 
Vertical Boring Mill, 226 
—Expanding, for an Adjusting Nut, 
188 

—Expanding, for an Automobile 
Flange, 186 

—Expanding, for a Bevel Pinion, 189 
—Expanding, for a Piston, 192 
—Expanding, Split-Ring Type, 184 
—for Milling Machine, 182 
—for Plain Lathe, 182 
—Knock-Off, for Threaded Collars, 
196 

—Special, for an Eccentric Pack¬ 
ing Ring, 198 

—Threaded and Knock-Off, 194 
—Threaded Knock-Off, for Vertical 
Boring Mill, 235 


—with Expanding Shoe, 183 
Artificial Abrasives, 97 
Attachment, Angular Generating, for 
Vertical Turret Lathe, 216 
—for Boring an Internal Radius, 
217 

—Radius-Forming, for Crowning 
Pulleys, 203 

—Radius-Generating, for an Engine 
Lathe, 201 

—Radius-Generating, for a Vertical 
Turret Lathe, 214 
—Tapping, for Drill Press, 123 
—Turning and Boring, for Packing 
Rings, 209 

—Turret Lathe, for Generating 
Bevel Pinions, 211 

Automobile Bearings, Testing Align¬ 
ment of, 391 

—Cam Shaft, Testing Throw of, 
396 

—Crank Shaft, Feeler Gauge for, 
399 

—Cylinders, Sliding Fixture for 
Boring, 233 

—Flange, Expanding Arbor for, 186 
—Fly-wheel, Fixture for, 224 
—Gas-Control Plate, Set-On Jig for, 
267 

—Hand Lever, Closed Jig for, 274 
—Oil-Pump Cover, Drill Jig for, 260 
—Oil-Pump Shaft, Bushing for, 270 
—Piston, Expanding Pin Chuck for, 
192 

—Piston Grinding Fixtures, 243 
—Transmission-Case Cover, Set-On 
Jig for, 266 

—Transmission-Case Cover, Trun¬ 
nion Jig for, 284 

—Universal Joint, Grinding Fixture 
for, 241, 246 


436 


INDEX 


437 


Ball-Bearing Cage, Internal Grinding 
Fixture for, 244 

Ball Bearings, Fluid Gauge for, 382 
Bearing End-Cap, Drill Jig for, 276 
Bearings, Testing Alignment of, 391 
Becker Continuous Milling Machine, 
Fixture for, 158 
Bench Vises, 117 
Bending Dies, 33 

Bevel Gear, Double, Expanding Arbor 
and Faceplate for, 226 
Bevel-Generating Attachment for a 
Turret Lathe, 211 

Bevel Pinions, Adjustable Grinding 
Fixture for, 250 
—Expanding Arbor for, 189 
—Generating Attachment for, on 
Turret Lathe, 211 

Bevel Ring Gear, Large, Grinding Fix¬ 
ture for, 251 

—Vertical Turret Lathe Attachment 
for, 216 

Blades, Hacksaw, Tooth Spacing of, 12 
Blanking Dies, 29 
Blocks, Johansson, 405 
Borax Solution as a Cutting Lubri¬ 
cant, 293 

Boring and Turning Attachment, Ec¬ 
centric, for Packing Rings, 209 
—an Internal Radius, 217 
Cylinders, Sliding Fixture for, 233 
Boring Bars, Flat-Cutter, 48 
—Types of, 49 

Boring Mill, Vertical, Fixtures for, 220 
—Vertical, Turning Tools for, 62 
Boring Tools, 46 

—Adjustable, for Tool-Room Work, 
48 

Box Tool for Turret Lathe Work, 58 
Bracket, Irregular, Fixture for, 172 
—Radius, Drill Jig for, 280 
—Rod-Supporting, Drill Jig for, 272 
—Slotted, Fixture for End Milling, 
145 

—Small, Open Jig for, 264 
Brass Founding, Crucibles in, 429 
Broaches for Irregular Holes, 95 
—for Four-Way Keyways, 94 
—for Round Holes, 92 
—for Square Holes, 91 
—Varieties of, 91 
Broaching a Round Hole, 92 
—a Square Hole, 91 
—Preliminary Treatment in, 90 
—Purposes of, 89 
Broaching Tools, Varieties of, 91 
Building for Storing Patterns, 421, 
427 


Bushing, Eccentric, Drill Jig for, 278 
—for an Oil-Pump Shaft, 270 
Business Aspects of Planning, 313 

Calipers, Micrometer, 378 
Cams, Electrical Contact Gauge for. 
401 

Cam Shaft, Testing Throw of, 396 
Castings, Rough, Self-Centering Fix¬ 
ture for, 168 

—Thin Aluminum, Fixture for, 169 
C-Clamps, 116 

Centering Fixture for a Rough Casting, 

168 

Chatter in Planer Tools, 22 
Chips, Removal of, by Stream of Lubri¬ 
cant. 295 

Chisels, Cold, Forms of, 12, 14 
Chucking Reamers, Fluted, 42 
—Rose, 42 

Chucks, Air-Operated, 130 
—Collet, 124 
-—Drill, and Sockets, 120 
—Four-Jawed Independent, 132 
—Geared Scroll, 129 
—Magic, 121 
—Magnetic, 240 
—Step, 126 
—Two-Jawed, 127 
Circular Cover Patterns, 416 
—Forming Tools, 71 
Clamp, Toolmakers, 115 
Classification of Files, 8 

—of Hand and Forged Tools, 7 
Clay Crucibles, Manufacture of, 429 
Closed Jigs, 270 

—for a Bearing Cap, 276 
—for a Rod-Supporting Bracket, 
272 

—for an Oil-Pump Bushing, 270 
—for Automobile Hand Lever, 274 
Cold Chisels, 12 
—Angles on, 15 
—Forms of, 14 

Collars, Threaded, Knock-Off Arbor 
for, 196 

Collets and Chucks, 125 
Combination Pattern for Pulleys or 

Gears, 424 

Composition of Cutting Lubricants, 291 
Compound Dies, 31 
Concentricity Indicating Gauge, 404 
Conditions of Manufacture, 2 
Connecting Rod, Automobile, Simple 
Straddle-Milling Fixture for, 
141 

—Automobile, Double Straddle- 

Milling Fixture for, 143 


438 


INDEX 


—Bearings, Testing Alignment of, 
391 

—Face-Plate Fixture for, 172 
Continuous Milling Machines, 154 
—Becker, Fixture for, 158 
Continuous Milling Fixture for Auto¬ 
mobile Cylinders, 156 
—Simple Type of, 155 
Contours, Flush-Pin Gauges for, 389 
Cooling by Lubrication in Cutting, 294 
Cope, Definition of, 409 
Core Drills, 38 
—Example of, 39 
Cores and Core Boxes, 411 
—Baked, 412 
Cost Estimation, 337 
Counterbalance, Adjustable, for a 
Face-Plate Fixture, 175 
Counterbalanced Fixture for a Con¬ 
necting Rod, 172 
Counterbores, 39 
—Types of, 40 

Crank Shaft, Feeler Gauge for, 399 
Cross-Slide for Generating Angular 
Cut on Ring Gears, 208 
Crown, Pulley, Forming the, 203 
Crucibles, Care in the Use of, 432 
—Clay, Manufacture of, 429 
—Graphite, Manufacture of, 430 
—Pouring the, 433 
—Storage of, 432 
Curling Dies, 33 

Curved Surfaces, Generating, 200 
Cutters, Angular, 79 
—Milling, 75 
—Slotting, 78 

Cutting Action of Lathe Tools, 23 
—of Planer Tools, 21 
Cutting Dies, 30 

Cutting Fixtures, Adaptability of, 238 
Cutting Lubricant, Effect of, on Speeds 
and Feeds, 309 
Cutting-Off Tools, 64 
Cutting Speed, Definition of, 301 
—Formula for Determining, 302 
—Table of, 307 

Cutting Tools, Lubrication of, 289 
Cylinders, Automobile, Continuous 
Milling Fixture for, 156 
-External, Ring Gauges for, 368 
—Sliding Fixture for Boring, 233 
Cylinder Grinding, 108 
Cylindrical Grinding, External, Hold¬ 
ing Work for, 239 
—Methods, 104 

Cylindrical Holes, Plug Gauges for, 
357 


Depth Gauge, Flush-Pin, 386 
Designer, Tool, Work of the, 315 
Details of Manufacturing, 1 
Dial Indicator, Ames, 379 
Dies, Bending, 33 
—Blanking, 29 
—Compound, 31 
—Curling, 33 
—Cutting, 30 

—Dove-Tailed Drop Forge, Ex¬ 

ample of, 27 
—Drawing, 33 

—Follow, Example of, 30, 32 
—Forming, 32 
—Gang, Example of, 33 
—Progressive, Example of, 32 
—Shaping, 30 
—Sub-press, 34 
—Tandem, 31 
—Taps and Holders, 136 
—Trimming, Example of, on Rough 
Forging, 30 

Dimensions, Limiting, on Drawings, 

356 

Distortion in Fragile Work, Fixture to 
Prevent, 228 
—in Patterns, 423 
Double Flush-Pin Depth Gauge, 390 
—Indexing Fixture for Straddle 
Milling, 149 

—Spline-Milling Fixture, 161 
—Straddle-Milling Fixture for a 
Connecting Rod, 143 
Dove-Tailed Drop-Forge Dies, Example 
of, 27 

Drag, Definition of, 409 
Drawing Dies, 33 

Drawings, Marking Limits on, 356 
Drill Chucks and Sockets, 120 
Drill Jig, Closed, for a Bearing Cap, 
276 

—for a Crooked Lever, 283 
—for an Eccentric Bushing, 278 
—for an Oil-Pump Cover, 260 
—for a Radius Bracket, 280 
—for a Rod-Supporting Bracket, 272 
—Functions of, 253 
Drill Jigs, Open, 253 
—for a Lever, 261 
—for a Lever with Stud Locater 
263 

—Plate, with Supplementary Sup¬ 
porting Ring, 258 

Drill Press, Tapping Attachment for, 
123 

Drills, Core, 38 
—Flat Twist. 38 


INDEX 


439 


—Shapes and Forms, 35 
—Spotting, 36 
—Twist, 37 
—Types of, 36 
Drive Fit, Definition of, 347 
—Table of Tolerances for, 354 
Drop-Forge Dies, Dove-Tailed, Ex¬ 
ample of, 27 

—with Space for Receiving Fin, 29 
Drop Forging, Method of Providing 
Holes for, 31 
—Principles of, 26 

Eccentric Fixture for a Ring Pot, 177 
—Swinging, 178 

Eccentric Packing Ring, Special Arbor 
for, 198 

—Turning Attachment for Packing 
Rings, 209 

—Work, Simple Fixture for Ma¬ 
chining, 231 

Electrical Contact Gauge for Cams, 401 
End-Cap, Bearing, Drill Jig for, 276 
End Milling a Slotted Bracket, Fix¬ 
ture for, 145 

Engine Lathe, Simple Radius-Generat¬ 
ing Attachment for, 201 
—Simple Recessing Tool for, 51 
Equipment, Standard, for Tool Crib, 
120 

—Standard Tool, for the Shop, 110 
Estimates, Making the, 339 
—on Labor Expense, 340 
—on Overhead Expense, 343 
Estimating Costs, 337 
Expanding Arbor and Faceplate for 
Vertical Boring Mill, 226 
—for an Adjusting Nut, 188 
—for an Automobile Flange, 186 
—for an Automobile Piston, 192 
—for a Bevel Pinion, 189 
—Split-Ring Type, 184 
Expanding Pin Chuck for a Piston, 
192 

Expanding Shoe Type of Arbor, 183 
External Cylindrical Grinding, Hold¬ 
ing Work for, 239 
—Form Grinding, 106 
—Gauges, 364 

—Tapers, Grinding Methods for, 106 

Face-Plate, Expanding Arbor and, for 
Vertical Boring Mill, 226 
Face-Plate Fixture, Counterbalanced, 
for a Connecting Rod, 172 
—for an Irregular Bracket, 172 
—for a Ring Pot, 177 
—for Cutting Packing Rings, 166 


—for Hub Flange, 167 
—for Quantity Production, 165 
—for Thin Aluminum Castings, 169 
—Self-Centering, for Rough Casting, 
168 

—Standard, for Engine Lathe, 165 
—Swinging Eccentric, 178 
—with Adjustable Counterbalance, 
175 

—with Safeguarding Devices, 172 
Factors Influencing Selection of Mill¬ 
ing Machines, 73 

Feeds and Speeds, Effect of Cutting 
Lubricant on, 309 
—Relation of, to Cutting Speeds, 
304 

Feeler Gauge for a Crank Shaft, 399 
Female Master Gauge for Testing Male 
Taper Gauges, 361 
—Taper Limit Gauge, 372 
—Thread Gauge, 374 
Female Taper Gauge, Reference Gauge 
for, 373 

Files, Classes of, 8 
—Forms of, 9 

Fin, Removal of, in Drop Forging, 28 
Fire Protection in Pattern Storage, 
428 

Fishtail Cutters, 78 
Fits, Variety of, in Manufacture, 347 
Fixture, Continuous Milling, for Cyl¬ 
inders, 156 

—Counterbalanced, for a Connecting 
Rod, 172 

—Cutting, Adaptability of, for 
Grinding, 238 

—Double-Indexing, for Straddle 
Milling, 149 

—Eccentric, for a Ring Pot, 177 
—Face-Plate, for Quantity Produc¬ 
tion, 165 

—for Angular Milling, 147 
—for an Irregular Bracket, 172 
—for a Fragile Aluminum Casting, 
Vertical Boring-Mill, 228 
—for Becker Continuous Milling 
Machine, 158 

—for Continuous Milling, Simple 
Type of, 155 

—for Double Spline Milling, 161 
—for End Milling a Slotted Bracket, 
145 

—for Form Milling, 148 
—for Gang Milling, 145 
—for Holding Automobile Fly¬ 
wheel, 224 

—for Plain and Straddle Milling, 
139 


440 


INDEX 


—for Spline Milling, 160 
—for Thin Aluminum Castings, 169 
—for Thin Work, 221 
—for Vertical Boring Mills, 220 
—Grinding, for Universal Joint, 
241, 246 

—Index Milling, for Quantity Pro¬ 
duction, 150 

—Nature and Variety of, 139 
—Simple, for Machining an Eccen¬ 
tric, 231 

—Sliding, for Boring a Pair of 
Cylinders, 233 

—Special, with Tapered Plug Lo- 
cater, 224 

—Straddle-Milling, for a Connect- 
ting Rod, 141 
—Swinging Eccentric, 178 
—with Adjustable Counterbalance, 
175 

—with Safeguarding Devices, 172 
Flange, Automobile, Expanding Arbor 
for, 186 

Flask, Molding, 409 
Flat-Chitter Boring Bars, 48 
Flat Twist Drills, 38 
Flood Lubrication, for Cutting, 298 
Fluid Gauge, Prestwich, 380 
Flush-Pin Gauges, 385 
—Double, 390 
—for Contours, 389 
—for Tapers, 388 
—with Dial Indicator, 387 
Fluted Reamers, Plain, 42 
Flywheel, Automobile, Fixture for, 224 
Force Fit, Definition of, 348 

—Table of Tolerances for, 354 
Ford Motor Plant an Example of Plan¬ 
ning, 315 
Forged Tools, 1 
—Varieties of, 19 
Forging, Drop, Principles of, 26 
Follow Dies, Example of, 32 
Formed Milling Cutters, 81 
Form Grinding, External, 106 
Forming and Grooving Attachment for 
Pistons, 206 

Forming Attachment, Radius, for 
Crowning Pulleys, 203 
Forming Dies, 32 
Forming Tools, 68 
—Circular, 71 

—for Turret Lathe Work, 57 
—Rectangular, 68 
Form Milling, Fixture for, 148 
Formula for Determining Cutting 
Speeds, 302 

Four-Jawed Independent Chuck, 132 


Four-Way Keyway Broaches, 94 
Free-Hand Sketches in Laying Out 

Work, 330 

Gang Dies, Example of, 33 
Gang Milling, Fixture for, 145 
Gas-Control Plate, Set-on Jig for, 267 
Gauges, Ames Dial Test, 380 

—Concentricity Indicating, 404 
—Electrical Contact, 401 
—External, 364 

—Feeler, for a Crank Shaft, 399 
—Female Thread, 374 
—Flush-Pin, 385 

—Indicating, for a Cam Shaft, 396 
—Indicator, for Testing Alignment, 
391 

—Internal Limit, 357 
—Internal Taper, 359 
—Johansson, 405 

—Master, for Female Taper Cauges, 
373 

—Master, for Male Taper Gauges, 

361 

—Micrometer, 378 
—Plug, 358 
—Prestwich Fluid, 380 
—Profile and Indicating, 376 
—Profile Inspection, 402 
—Receiver, 370 
—Ring, 368 
—Snap, 365 
—Taper Ring, 372 
—Templet, 367 
—Thread, Male, 362 
Gauging, Terminology of, 349 
Geared Scroll Chucks, 129 
Gears, Bevel Ring, Grinding Fixture 
for, 251 

—Bevel Ring, Vertical Turret Lathe 
Attachment for, 216 
—Combination Patterns for, 424 
-—Double Bevel, Expanding Arbor 
and Faceplate for, 226 
—Ring, Cross-Slide for Generating 
Angular Cut on, 208 
—Spur, Adaptable Grinding Fix¬ 
ture for, 248 

Gear Molding Machine, 425 
Gear-Tooth Milling Cutters, 81 
Generating Angular Cut on Ring Gears, 
Cross-Slide for, 208 
—Curved Surfaces, 200 
Generating Attachment, Angular, for 
Vertical Turret Lathe, 216 
Go and Not Go Gauges, 358 
Goose-Neck Threading Tools, 67 


INDEX 


441 


Graphite Crucibles, Composition of, 
430 

—Manufacture of, 430 
Grinding, External Cylindrical, Hold¬ 
ing Work for, 239 
—External Forms, 106 
—External Tapers, 106 
—Interior of Automobile Cylinders, 
108 

Grinding Fixtures, Adaptable, for 
Spur Gears, 248 

—Adjustable, for Bevel Pinions, 250 
—for Automobile Piston, 243 
Grinding Fixture for a Large Bevel 
Ring Gear, 251 

—for Universal Joint, 241, 246 
—Internal, for a Ball-Bearing Cage 
244 

Grinding Material, 97 
Grinding Methods, Cylindrical, 104 
—Internal, 107 
—Surface, 100 
Grinding Tools, 24 
Grinding-Wheels, Shapes of, 99 
Grooving Attachment for Pistons, 206 

Hacksaws, 10 

Hand and Forged Tools, 1 

Hand Lever, Automobile, Jig for, 274 

Hand Vises, 114 

Head, Multiple Turning-Tool, 62 
Hob Milling Cutter, 83 
Holders for Taps and Dies, 136 
—for Tools, 25 

Holding Work, Necessity for, in Mill¬ 
ing, 140 

Holes, Cylindrical, Plug Gauges for, 
357 

—in Drop Forgings, Method of Pro¬ 
viding for, 31 

—Irregular, Broaches for, 95 
—Round, Broaching Cut for, 92 
—Square, Broaching Cut for, 91 

_Standard, Table of Tolerances for, 

352 

Hollow Mills, 55 
—Types of, 56 

Horizontal Turret Lathe, Internal 
Lubrication of, for Drilling, 296 
Hub Flange, Face-Plate Fixture for, 

167 

Independent Chuck, Four-Jawed, 132 
Index Milling a Pair of Levers, 149 

_Fixture for Quantity Production, 

150 

Index of Machine Tools, 319 
—of Patterns, 425 


Indicating Gauge for a Cam Shaft, 396 
—for Concentric Surfaces, 404 
Indicator Gauge for Testing Align¬ 
ment, 391 

Indicators, Dial, 379 
Inserted-Blade Milling Cutter, 85 
—Reamers, 43 

Inspection Gauge, Profile, 402 
Instruments of Precision, 377 
Interchangeable Manufacture, 3 
—Degree of Accuracy in, 346 
Interchangeable Work, Limits for, 351 
Interlocking Milling Cutters, 86 
Internal Grinding Fixture for a Ball- 
Bearing Cage, 244 
Internal Grinding Methods, 107 
—Limit Gauges, 357 
—Radius Boring Attachment, 217 
—Taper Gauges, 359 
Irregular Bracket, Face-Plate Fixture 
for, 172 

Jigs, Closed, 270 

—for Automobile Hand Lever, 274 
—for an Oil-Pump Bushing, 270 
—for a Rod Supporting Bracket, 
272 

Jig, Closed Drill, for a Bearing Cap, 
276 

—for a Crooked Lever, 283 
—for an Eccentric Bushing, 278 
—for a Radius Bracket, 280 
Jig Drill, for an Oil-Pump Cover, 260 
—Functions of, 253 
Jig, Open, for a Lever, 261 

—for a Lever with Stud Locater, 263 
—for a Small Bracket, 264 
Jigs, Plate, with Supplementary Sup¬ 
porting Ring, 258 

Jig, Set-On, for a Gas-Control Plate, 
267 

—for a Transmission-Case Cover, 
266 

Jigs, Simple Plate, for Drilling, 256 
Jig, Trunnion, for a Transmission- 
Case Cover, 284 
Johansson Gauges, 405 

Knock-Off Arbors for Threaded Col¬ 
lars, 196 
—Threaded, 194 

—Threaded, for Vertical Boring 
Mill, 235 

Keyway Broaches, 91 

Lard Oil as a Cutting Lubricant, 291 
Lathe, Plain, Arbor for, 182 
Lathe Tools, Cutting Action of, 23 


442 


INDEX 


Labor, Skilled and Unskilled, in Es¬ 
timating Costs, 340 
Laying Out Work in the Machine 
Shop, 317 

Layout of Jigs, Fixtures, Tools, and 
Gauges, 322 

—of Machine-Tool Equipment, 319 
—of Operations, 318 
—of Operation Sheets, 323 
—Sheets, 330 

Lead of Thread, Definition of, 362 
Lever, Crooked, Drill Jig for, 283 
—Hand, Jig for, 274 
—Index Milling a Pair of, 149 
—Open Jig for, 261 
—Open Jig for, with Stud Locater, 
263 

Limit, Definition of, 350 
Limit Gauges, Internal, 357 

—Taper, for Internal Tapered Hole, 

360 

Limiting Dimensions on Drawings, 356 
Limits for Interchangeable Work, 351 
Locating Work, V-Block Principle of, 
170 

Lubricants, Composition of, for Cut¬ 
ting Aluminum, 293 
—Composition of, for Cutting Steel, 
293 

—Effect of, on Cutting Speeds and 
Feeds, 309 

—Stream of, for Removing Chips, 
295 

Lubricating a Horizontal Turret Lathe, 
Internally, 295 

—a Turret Lathe through the Spin¬ 
dle, 296 

—a Vertical Turret Lathe, 299 
Lubrication, Flood, for Cutting, 298 
—of Cutting Tools, 289 

Machine Equipment, 119 
—for Molding Gears, 425 
Machine-Tool Equipment, 319 
—Index, 319 
—Record Card, 321 
Machine Vises, 134 
Magic Chuck, 121 
Magnetic Chucks, 240 
—Description of, 100 
Male Master Gauge for Testing Fe¬ 
male Taper Gauges, 373 
—Taper Gauge, Reference Gauge for, 

361 

—Thread Gauge, 362 
Mandrel, Definition of, 181 
Manufacturing Details, 1 
Manufacturing Vises, 134 


Marking the Pattern, 426 
Master Gauge for Male Taper Gauges, 
361 

—for Female Taper Gauges, 373 
Metal Patterns, Advantages of, 424 
Micrometer Gauges, Construction Fea¬ 
tures of, 378 

Milling Cutters, Angular, 79 

—Formed, 81 
—Gear-Tooth, 81 
—Hob, 83 
—Inserted-Blade, 85 
—Interlocking, 86 
—Plain, 86 
—Shell-End, 77 
—Spiral, 75 
—Straddle, 85 
—Straight-Fluted, 75 
Milling, Gang, Fixture for, 145 
—Processes, 72 

Milling Machine, Arbor for, 182 

—Factors Influencing Selection of, 
73 

Mills, Hollow, 55 

Mineral Oil as a Cutting Lubricant, 
291 

Molding a Flanged and Ribbed Pat¬ 
tern, 418 

—Clay Crucibles, 429 
—Method, 409 

Molding Machine for Gears, 425 
Molding Sand, 411 
Morse Taper, 120 

Multiple-Spindle Drilling Machines, 
Drill Jigs for, 253 
Multiple-Turning Tool Head, 62 

Natural Abrasives, 97 

Newall Engineering Co., Table of 

Limits, 355 

Nowel, Definition of, 409 

Nut, Adjusting, Expanding Arbor for, 

188 

Oil as a Cutting Lubricant, 291 
Oiling Arrangement, Internal, for 
Drilling on Horizontal Turret 
Lathe, 296 

Oil-Pump Cover, Drill Jig for, 260 
—Shaft, Bushing for, 270 
Open Drill Jigs, 253 
Open Jig for a Lever, 261 

—for a Lever with Stud Locater, 
263 

—for a Small Bracket, 264 
Open-Side Turning Tools, 60 
Operation Layout, 318 
Operation Sheets, Layout of, 323 


INDEX 


443 


Overhead Expense, Estimating the, 343 
Overhead Turning Tools, 60 

Packing Ring, Eccentric, Special Arbor 
for, 198 

—Eccentric Turning and Boring At¬ 
tachment for, 209 
—Fixtures for Cutting, 166 
Packing Ring Pot, Swinging Eccentric 
Fixture for, 179 
Parallels, 112 

Pattern Makers’ Tools, 419 
Pattern Records, Importance of, 421 
—Cards, 425 

Patterns, Circular Cover, 416 

—Combination, for Pulleys and 
Gears, 424 

—Composition of, 407 
—Construction of, 408 
—Finish of, 422 
—Fire Protection of, 428 
—Flanged and Ribbed, 418 
—Index, 425 
—Location of, 427 
—Marking System for, 426 
—Metal, Advantages of, 424 
—Method of Molding, 410 
—One-Piece, 409 
—Quality of, 422 
—Ring and Spider, 424 
—Sectional, 423 
—Skeleton, 419 
—Sweep, 419 
—Three-Part, 417 
—Two-Part, 414 
—Warpage of, 423 
Pattern Storage Building, 421, 427 
—Fire Prevention in, 428 
—Method, 427 

Permanent Tools, Definition of, 5 
Perishable Tools, Definition of, 5 
Piece-Work Prices, Determination of, 
335 

Piloted Turning Tool for Rapid Pro¬ 
duction, 61 

Pin Chuck, Expanding, for a Piston, 
192 

Pinions, Bevel, Adjustable Grinding 
Fixture for, 250 
—Expanding Arbor for, 189 
—Turret Lathe Attachment for Gen¬ 
erating, 211 
Pipe Vises, 117 

Piston, Automobile, Expanding Pin 
Chuck for, 192 

—Cast-Iron, Time-Study Sheet on, 
333 


—Cast-Iron, Tool and Operation 
Sheet for, 324 

—Forming and Grooving Attach¬ 
ment for, 206 

—Generating Curved Ends of, 201 
■—Grinding Fixture, 243 
—Prestwich Gauge for, -383 
—Tool Layout Sheets for, 328 
Plain Chucking Reamers, 42 
—Fluted Reamers, 42 
—Milling Cutter, 86 
Plain Milling, Fixtures for, 139 
Planing Tools, 87 
—Chatter in, 22 
—Cutting Action of, 21 
Planning, Business Aspects of, 313 
Plate Jig, Simple, for Drilling, 256 
—with Supplementary Supporting 
Ring, 258 

Plug Gauges for Cylindrical Holes, 357 
Plug Locater, Tapered, for Holding a 
Flywheel, 224 

Poppet Valve, Receiver Gauge for, 371 
Pouring the Crucible, 433 
Precise Measuring, 377 
Prestwich Fluid Gauge, 380 
Principles of Drop Forging, 26 

—of V-Block in Locating Work, 170 
Profile and Indicating Gauges, 376 
—Inspection Gauge, 402 
Progressive Dies, Example of, 32 
Pulleys, Combination Patterns for, 424 
—Facing on Vertical Turret Lathe, 
214 

—Forming the Crown of, 203 
Push Fit, Definition of, 347 

—Table of Tolerances for, 354 
Pump Cover, Oil, Drill Jig for, 260 

Quality of Patterns, 422 

Radius Boring, Internal, Attachment, 
217 

Radius Bracket, Drill Jig for, 280 
Radius-Forming Attachment for Crown¬ 
ing Pulleys, 203 

Radius-Generating Attachment for a 
Vertical Turret Lathe, 214 
—Attachment, Simple, for an En¬ 
gine Lathe, 201 
Reamers, 41 

—Inserted-Blade, 43 
—Plain Chucking, 42 
—Plain Fluted, 42 
—Rose Chucking, 42 
—Taper, 44 

Receiver Gauge, for Taper Pins, 370 


444 


INDEX 


Recessing Tools, 50 

—for a Large Steel Casing, 54 
—for Turret Lathe Work, 52 
—on an Engine Lathe, 51 
Record Cards for Patterns, 425 
—of Machine Tools, 321 
Records, Pattern, Importance of, 421 
Rectangular Forming Tools, 68 
—Magnetic Chucks, 240 
Reference Gauges, Female, 361 
—Male, 373 

Rests, Roller-Back, for Adjustable 
Turning Tool, 59 
Ring and Spider Patterns, 424 
Riqg Gauges for Cylindrical Work, 368 
—for Tapers, 372 

Ring Gear, Bevel, Grinding Fixture 
for, 251 

—Vertical Turret Lathe Attach¬ 
ment for, 216 

Ring Gears, Cross-Slide for Generating 
Angular Cut on, 208 
Ring Pot, Face-Plate Fixture for, 177 
—Packing, Swinging Eccentric Fix¬ 
ture for, 179 

Rock Drill, Vertical Boring Mill Fix¬ 
ture for, 235 

Rod-Supporting Bracket, Drill Jig for, 
272 

Roller-Back Rests for Adjustable Turn¬ 
ing Tool, 59 

Rose Chucking Reamers, 42 
Rotary Magnetic Chucks, 240 
Round Holes, Broaching Cut for, 92 
Running Fit, Definition of, 347 
—Table of Tolerances for, 353 

Safety Devices on a Face-Plate Fix¬ 
ture, 172 

Scheduling Work in the Machine Shop, 
316 

Scrapers, 15 
—Types of, 18 
-^-Use of, 16 

Screws, Measuring the Lead of, 364 
—Templet Gauge for, 368 
Scroll Chucks, Geared, 129 
Secret of Cost Estimation, 340 
Sectional Patterns, 423 
Self-Centering Fixture for a Rough 
Casting, 168 

Set-On Jig for a Gas-Control Plate, 
267 

—for a Transmission-Case Cover, 
266 

Shafts, Dial Test Gauge for Inspecting, 
380 


—Limits for Length of, 355 
—Tapered, Flush-Pin Gauge for, 388 
Shaping Dies, 30 
Shell-End Milling Cutters, 77 
Shells, Gauge for Indicating Concen¬ 
tricity of, 404 

Shop Equipment, Standard, 110 
Side Milling Cutter, 85 
Skeleton Patterns, 419 
Sketches, Free-Hand, for Work, 330 
Sliding Fixture for Boring a Pair of 
Cylinders, 233 
Slotting Cutters, 78 
Snap Gauge, for Cylindrical Work, 365 
—for General Dimensions, 366 
Sockets, Drill, 120 

Sodawater as a Cutting Lubricant, 292 
Speeds and Feeds, Definition of, 301 
—Effect of Cutting Lubricants on, 
309 

—General Rules for, 310 
—Importance of Proper, 307 
Speeds, Cutting, Formula for Deter¬ 
mining, 302 

—Cutting, Table of, 307 
—Relation of, to Feeds, 304 
Spider and Ring Patterns, 424 
Spiral Milling Cutters, 75 
Spline-Milling Fixtures, 160 
Split-Ring Expanding Arbor, 184 

—Expanding Arbor for an Adjuct- 
ing Nut, 188 
Spotting Drill, 36 

Spur Gears, Adaptable Grinding Fix¬ 
ture for, 248 

Square Hole, Broaching Cut for, 91 
Standard Face Plate for Engine Lathe, 

165 

—Tool Equipment for the Shop, 110 
Steel, Lubricants for Cutting, 293 
Step Chucks, 126 
Storage of Crucibles, 432 
—of Patterns, 427 
Straight-Edges, 112 
Straight-Fluted Milling Cutters, 75 
Straddle Milling Cutter, 85 
Straddle Milling, Double-Indexing Fix¬ 
ture for, 149 

Straddle-Milling Fixture for a Con¬ 
necting Rod, 141 

—Working from a Finished Surface, 
143 

Stud Locater for Open Jig, 263 

Sub-Press Dies, 34 

Surface Grinding Methods, 100, 102 

Surface Plates, 111 

Sweep Patterns, 419 

Swinging Eccentric Fixture, 178 


INDEX 


445 


Tandem Dies, 31 

Tapered Hole, Holding Work by the, 
225 

Tapered Plug Locater for Holding a 
Flywheel 224 

Taper Gauge, Female, Reference Gauge 
for, 373 
—Internal, 359 

—Male, Reference Gauge for, 361 
Taper Pins, Receiver Gauge for, 370 
Taper Reamers, 44 
Taper Ring Gauge, 372 
Tapers, Designation of, 120 
—Flush-Pin Gauges for, 388 
—Grinding External, 106 
Tapping Attachment for Drill Press, 
123 

Taps, Dies, and Holders, 136 
Tee-Slot Cutters, 78 
Templet Gauges, 367 
—for a Screw, 368 
Thin Work, Fixture for, on Vertical 
Boring Mills, 221 
Thread-Chasing Tools, 66 
Threaded and Knock-Off Arbors, 194 
Threaded Collars, Knock-Off Arbor for 
196 

Threaded Knock-Off Arbor for Verti¬ 
cal Boring Mill, 235 
Thread Gauge, Inspection of, by Fluid 
Gauges, 384 
—Female, 374 
—Male, 362 
Threading Tools, 65 
—Goose-Neck, 67 
Three-Part Patterns, 417 
Time Factor in Cost Estimates, 337 
Time-Study Sheets, 332 
Tolerance, Definition of, 349 

—for Push, Drive, and Force Fits, 
Table of, 354 

—for Running Fits, Table of, 353 
—for Standard Holes, Table of, 352 
Tool and Operation Sheet, 324 
Tool Crib, Equipment for, 120 
Tool Engineering, Importance of, 315 
Tool Equipment, 5 

—Standard, for the Shop, 110 
Tool Holders, 25 
Tool Layout, 322 
—Sheet, 328 

Toolmakers’ Adjustable Boring Tool, 
48 

—Tool Equipment of, 111 
Tools, Boring, 46 
—Broaching, 91 
—Cutting-Off, 64 
—Forming, 68 


—for Pattern Making, 419 
—Grinding, 24 

—Hand and Forged, Classification 
of, 7 

—Lathe, 23 

—Perishable, Definition of, 5 
—Permanent, Definition of, 5 
—Planer, 21, 87 
—Recessing, 50 
—Threading, 65 

Transmission-Case Cover, Set-On Jig 
for, 266 

—Trunnion Jig for, 284 
Trimming Die, Example of, on Rough 
Forging, 30 
Trunnion Jig, 284 

Turning and Boring Attachment, Ec¬ 
centric, for Packing Rings, 209 
Turning-Tool Head, Multiple, 62 
Turning Tools, 57 

—Adjustable, with Roller-Back 
Rests, 59 

—for Vertical Boring Mills, 62 
—Open-Side, 60 
—Overhead, 60 

—Piloted, for Rapid Production, 61 
Turret-Lathe Attachment for Generat¬ 
ing Bevel Pinions, 211 
Turret Lathe, Box Tool for, 58 

—Bullard Vertical, Cutting-Lubri¬ 
cant System for, 299 
—Forming Tool for, 57 
—Horizontal, Internal Lubrication 
of for Drilling, 296 
—Lubrication of, through Spindle, 
296 

—Machine-Tool Record Card for, 
321 

—Recessing Tools for, 52 
—Vertical, Angular Generating At¬ 
tachment for, 216 
—Vertical, Radius-Generating At¬ 
tachment for, 214 
Twist Drills, 37 
—Flat, 38 

Two-Jawed Chucks, 127 
Two-Lip Slotting Cutters, 78 

Universal Joint, Grinding Fixture for, 
241, 246 

Valve Stem, Receiver Gauge for, 371 
V-Blocks, 116 

—Principle of, 170 
Vertical Boring Mill, Expanding Arbor 
and Face-Plate for, 226 
—Fixtures for, 220 


446 


INDEX 


—Fixture for a Fragile Aluminum 
Casting, 228 

—Threaded Knock-Off Arbor for, 235 
—Turning Tools for, 62 
Vertical Turret Lathe, Angular Gen¬ 
erating Attachment for, 216 
—Cutting-Lubricant System for, 299 
—Radius-Generating Attachment for, 
'214 


Vises, Bench, 117 
—Hand, 114 

—Machine and Manufacturing, 134 
—Pipe, 117 

Warpage of Patterns, 423 
Worm-Gear Hob Milling Cutter, 83 
Worm-Gear Sector, Fixture for, 176 





































